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Упит dcterms_creator_txt:Kličković M.

984 items

  • A Lexical Approach to Acronyms and their Definitions

    Cvetana Krstev, Duško Vitas, Ranka Stanković (2015)
    In this paper we present a comprehensive approach to acronyms for Natural-Language Processing (NLP) of Serbian texts. The proposed procedure includes extraction of acronyms and their definitions that are usual Multi-Word Units (MWUs), shallow parsing of MWUs that enables MWU lemmatization and production of entries in morphological electronic dictionaries, both for MWU and acronyms, that are provided with grammatical, syntactic, semantic and domain information. This approach enables representation that reflects complex relations between acronyms and their definitions.
    ... ns. In AMIA Annual Symposium Proceedings, volume 2012. American Medical Informatics Association. Pustejovsky, J., J. Castano, B. Cochran, M. Kotecki, and M. Morrell, 2001. Automatic extraction of acronym- meaning pairs from MEDLINE databases. In Medinfo 2001: Proc. of the 10th World Congress on ...
    ... manually 21 multiple entries 19 e-dict_MW_forms 9,956 6 corpus 23MW acr. inflects 333 acronyms 987 acr. in masc. 323 acr. in fem. 64 acr. both m&f 35 acr. in plural 2 7 acronyms 987 e-dict_acr_forms 6,946 Table 1: Results of the procedure on our corpus The majority of (acronym, definition) ...
    ... Construction and Disambiguation (abstract). 3rd Parseme General Meeting – Poster Session. Krstev, C., R. Stanković, I. Obradović, D. Vitas, and M. Utvić, 2010. Automatic construction of a morpho- logical dictionary of multi-word units. In IceTAL, vol- ume 6233 of LNCS. Springer. Krstev, C. and ...

  • Геомагнетни премер на секуларној станици KELE-1001 (Келебија) у мају 2018. године

    Панта Андрејић (2024)
    У овом раду је приказана методологија геомагнетног премера на секуларној станици Келебија. Мерења су изведена у периоду од 08. до 12. маја 2018. године и састојала су се од регистрације дневних варијација, мерења апсолутних вредности угловних елемената и компонената вектора геомагнетог поља и одређивања астрономског севера. Овај вид мерења се често назива магнето-варијациона мерења и саставни су део државног геомагнетог премера за праћење и проучавање геомагнетног поља у систему простор-време.У оквиру обраде података израчунате су апсолутне и базне вредности ...
    секуларна станица, регистрација варијација, апсолутна и базна мерења
    ... TDpOKOMIIOHCHTHOT (biryKcrejr MarHeToMeTpa — Magson 11. Ha pacrojapy ojr 30 no 40 m oJ Te no3HNHje, Ha HECMAaTHECTHUHOM CTaTHBy, OMO je IHIOCTaBJbĆH CCH3Op HpOTOHcKor HmpenecHoHor MarHeToMerpa GSM 19. Ha ynajbeHocTH OJ OKO 20 m, Ha 4 Cpe)HHH H3Meby no3HIHje CeH3Opa Ta )IBa MaTrHCTOMCTpa, OHO jc HOCTABJbCH ...
    ... 55255205, 706167 + A - _ — 60km Ceky.napHa cTaHiiia KEJIEBHJA Canuka 1. Pedpepenmna oeoaonemua Mpeoica ceKynapHux cmaHuua y Penyonuuyu Cpouju (PI M). CekyaapnHa cmaHuua Kene6uja je oaHaueHa upaeHuuM keaOopamow (nopmai I eo Cpouja) MerojnonorHja reOMarHeTHOTr IIpeMepa Ha CeKyJIapHMM CTaHHHAMa ...
    ... TINIOJba. TeoMarHeTHa BapHjarmoHa MepeMba OOyXBaTajy CCKyHJHC H/HHH MMHHyTHc perHcTpanuje BapHjamMja KOMIIOHeHTA BeKTOPpa TeOMarHeTHor mojJba (D, H, Z m X, Y, Z KOMIOHeHT42) Ha JIoKalHjH CeKyJIapHe Oas3He craHHIIe y Tpajaby oJl 3 no 5 maHa. Ha cnanua 2 je npHKa3aH TDOKOMIIOHECHTHH ()nyKcrejr MarHeroMeTap ...

  • Kontaktni metamorfizam gornjokrednih sedimentnih stena Rudnika

    Kostić N. Bojan (2021)
    Kontaktni metamorfizam gornjokrednih sedimentnih stena na planini Rudnik ispitivan je na uzorcima iz pet bušotina. Definisano je šest varijeteta krednih stena (protolita) koji čine dve litološke jedinice izgrađene od klastičnog, karbonatnog i klastično-karbonatnog materijala. Vulkanskom aktivnosti na Rudniku formirana su vulkanska tela koja se utiskuju duž slojevitosti sedimentnih stena, a neka ih presecaju u vidu dajkova. Starost ovog vulkanskog događaja određena je na 23.9 miliona godina. Ovaj miocenski vulkanizam doveo je do kontaktno metamorfnih promena sedimentnih stena i obrazovanja skarnova ...
    Rudnik, kontaktni metamorfizam, sedimentne stene, hornfels, skarn, granati, vezuvijan
    ... 1195-1209 Terzić, M., Ristić, P. 1963: Vulkanske stene severozapadnog dela planine Rudnik. Geološki zavod Univerziteta u Beogradu, 30, p.109-124 Terzić, M., Milojković, R. 1967: Bazaltoidne stene Rudnika. Geološki zavod Univerziteta u Beogradu, 33, p.309-318 Toljić, M., Matenco, L., Stojadinović ...
    ... Rudniku 109 LITERATURA Anđelković, M. 1955: Prilog poznavanju geološkog sastava i tektonskog sklopa terena između Ljiga, Ugrinovca i G. Branetića (Šumadija). Geološki anali Balkanskog poluostrva, 23, p. 27-44 Anđelković, M. 1978: Stratigrafija Jugoslavije – Paleozoik i mezozoik ...
    ... Univerzitet u Beogradu, pp. 1017 Apted, M. J., Liou, J. G. 1983: Phase relations among greenschist, epidote-amphibolite, and amphibolite in a basalt system. American Journal of Seismology. 283-A, p. 328-354 Armbruster, T., Bonazzi, P., Akasaka, M., Bermanec, V., Chopin, C., Gieré, R., Heuss- ...

  • Mogućnost korišćenјa toplotnih pumpi sa otpadnom toplotom iz postrojenјa za prečišćavanјe otpadnih voda kao toplotnim izvorom

    Dejan Ivezić, Marija Živković, Aleksandar Madžarević, Boban Pavlović (2021)
    U narednom periodu se planira izgradnja nekoliko desetina sistema za prečišćavanje otpadnih voda u većim gradovima u Srbiji. Iskustva iz postrojenja koja su trenutno u radu, pokazuju da bi prečišćena otpadna voda, s obzirom na protok i temperaturu, mogla da predstavlja značajan izvor obnovljive energije. U radu su prikazani primeri dobre prakse korišćenja ove energije u sistemima daljinskog grejanja u zemljama Evropske unije. Analiziran je rad postrojenja za prečišćavanje otpadnih voda u Šapcu i razmotrena je mogućnost njegovog korišćenja ...
    toplotna pumpa, sistem daljinskog grejanja, postrojenje za prečišćavanje otpadnih voda
    ... hlađenje prostora u postojećim zgradama. 0 10 20 30 40 50 60 0 500 1000 1500 2000 2500 3000 3500 h e a t lo a d f o r D H g ri d i n M W hours per year Slika 3. Kriva godišnjeg opterećenja SDG u Šapcu [11] Kriva opterećenja u sistemu daljinskog grejanja je prikazana na Slici ...
    ... korišćenje OIE za proizvonju električne energije će predstavljati bitan stimulans za korišćenje toplotnih pumpi u SDG. LITЕRАTURА [1] Živković, M., Ivezić, D. Osnove energetike. Rudarsko-geološki fakultet, Beograd, 2019. [2] Heat Roadmap Europe, https://heatroadmap.eu/ [pristupljeno 15.01.2021] ...
    ... electric heat pumps in district heating systems, Energies, Vol 10, Issue. 4, pp 578, 2017. https://doi.org/10.3390/en10040578 [5] Ivezić, D., Živković, M., Madžarević, A. Efekti potencijalnog korišćenja postrojenja za preradu otpadnih voda kao energetskih izvora u sistemima daljinskog grejanja u Srbiji ...

  • Influence of Ag doping on the morphological and magnetic properties in CuO nanopowders

    Maria Čebela, Uroš Čakar, Vesna Lojpur, Maja Milošević, Sanja Krstić, Vladimir Dodevski, Milena Rosić (2023)
    ... Technologies, Institute for Multidisciplinary Research, University of Belgrade Faculty of Technology and Metallurgy, University of Belgrade e Z _ -— M, e V A7th o nfayanca dE _N 7CS CS - 20 23 the Serbian Society for Ceramic Materials { June 14-16. 2023. Belgrade Serbia — , b " AYNR 1 / V M_ TMK ...
    ... scanning electron microscopy (SEM). 1. T. Kimura, Y. Sekio, H. Nakamura, T. Siegrist, A.P. Ramires, Nafture Mater., 7 (2008) 291. 2. J. Hellsvik, M. Balestieri, T. Usui, A. Stroppa, A. Bergman, L. Berqvist, D. Pabhakaran, O. Eriksson, S. Picozzi, T. Kimura, J. Lorenzana, Phys. Rev. B, 90 (2014) ...

  • Improving Document Retrieval in Large Domain Specific Textual Databases Using Lexical Resources

    Ranka Stanković, Cvetana Krstev, Ivan Obradović, Olivera Kitanović (2017)
    Large collections of textual documents represent an example of big data that requires the solution of three basic problems: the representation of documents, the representation of information needs and the matching of the two representations. This paper outlines the introduction of document indexing as a possible solution to document representation. Documents within a large textual database developed for geological projects in the Republic of Serbia for many years were indexed using methods developed within digital humanities: bag-of-words and named ...
    ... Creating a dictionary of the whole document collection from all words selected in Step 4. For each term Tk in the document collection, k = 1, . . . M , where M is the size of the dictionary of document collection: (a) calculating document frequency dfk as the number of documents in the collection in which ...
    ... 6. Graovac, J.: Wordnet-based serbian text categorization. INFOtheca 14(2), 2a–17a (2013) 7. Gross, M.: The use of finite automata in the lexical representation of natural lan- guage. In: Gross, M., Perrin, D. (eds.) LITP 1987. LNCS, vol. 377, pp. 34–50. Springer, Heidelberg (1989). doi:10.1007/3- ...
    ... I., Utvić, M., Vitas, D.: A system for named entity recog- nition based on local grammars. J. Logic Comput. 24(2), 473–489 (2014) 14. Manning, C.D., Raghavan, P., Schütze, H.: Introduction to Information Retrieval, vol. 1. Cambridge University Press, Cambridge (2008) 15. Martinović, M.: Transfer ...

  • Present Situation and Alternative Water Supply Solutions for Northern Vojvodina (Serbia)

    Bojan Hajdin, Vesna Ristić-Vakanjac, Dušan Polomčić (2020)
    The northern part of the Autonomous Province of Vojvodina is situated in the central and southeastern sectors of the Pannonian Basin. Drinking water supply is provided by groundwater abstraction from depths of 60 to 200 m. The quality of that water is poor, especially due to high concentrations of arsenic which most water supply systems do not remove. Current planning documents call for the construction of large regional water supply schemes on the banks of the Danube and Tisa ...
    podzemne vode, regionalni sistem vodosnabdevanja, arsen

  • Anthropogenic impact on the groundwater regime: Case study of the Velika Morava alluvium

    Jovana Mladenović, Vesna Ristić Vakanjac, Milan Kresojević, Boris Vakanjac, Jugoslav Nikolić, Dušan Polomčić, Dragoljub Bajić (2023)
    The Velika Morava River originates at the junction of the Južna Morava and Zapadna Morava at the town of Stalać in Serbia. It is 185 km long and empties into the Danube. The Velika Morava River Basin occupies a land area of 37 444 km2. The river flows through central Serbia, which features the most fertile land and the highest population density in the country. Public water supply in this region of Serbia relies on groundwater formed in alluvial ...
    hydrology, surface water regime, groundwater regime, the Velika Morava River

  • Definisanje strukturnih odnosa primenom postupka horizontalni gradijent

    Snežana Ignjatović, Ivana Vasiljević, Natalija Jovanović (2019)
    Različiti postupci matematičkih transformacija se mogu primeniti na gravimetrijskim i magne tometrijskim podacima, kako bi se na istražnom terenu definisali strukturno-tektonski odnosi. U radu su prikazani rezultati dobijeni korišćenjem postupka horizontalni gradijent i ukupni horizontalni gradijent na gravimetrisjkim podacima. Navedeni postupci su pomogli da se detektuju kontakti sa velikim padnim uglom (vertikalni ili subvertikalni kontakti), koji se mogu interpretirati kao rasedi. Za test područije uzet je istražni prostor koji se nalazi na jugoistoku Srbije u okolini Vranjskog basena. Položaji ...
    gravimetrijski podaci, matematičke transformacije, rased, Vranjski basen
    ... GETECH. Advanced Processing and Interpretation of Gravity and Magnetic Data, Getech Kitson House Elmete Hall Leeds, UK, 2007. [8] Marović M, Toljić M, Rundić Lj, Milivojević J, Neo- alpine Tectonics of Serbia, Serbian Geological So- ciety, Beograd, 2001. SUMMARY THE APPLICATION OF HORIZONTAL ...
    ... Ignjatović S, Osnovi gravimetrije – pra- ktikum, Univerzitet u Beogradu - Rudarsko-geološki fakultet, Beograd, 2016. [2] Bilibajkić P, Mladenović M, Mujagić S, Rimac L. Tumač za gravimetrijsku kartu SFR Jugoslavije – Bu- geove anomalije 1:500 000, Savezni geološki zavod, Beograd, 1979. [3] Blakely ...

  • SASA Dictionary as the Gold Standard for Good Dictionary Examples for Serbian

    Ranka Stanković, Branislava Šandrih, Rada Stijović, Cvetana Krstev, Duško Vitas, Aleksandra Marković (2019)
    У овом раду представљамо модел за избор добрих примера за речник српског језика и развој иницијалних компоненти модела. Метода која се користи заснива се на детаљној анализи различитих лексичких и синтактичких карактеристика у корпусу састављених од примера из пет дигитализованих свезака речника САНУ. Почетни скуп функција био је инспирисан сличним приступом и за друге језике. Дистрибуција карактеристика примера из овог корпуса упоређује се са карактеристиком дистрибуције узорака реченица ексцерпираних из корпуса који садрже различите текстове. Анализа је показала да ...
    Српски, добри примери из речника, аутоматизација израде речника, издвајање својстава, Машинско учење
    ... 8. References Atkins, S. B. T. & Rundell, M. (2008). The Oxford Guide to Practical Lexicography. Oxford: Oxford University Press. Bird, S., Loper, E. & Klein E. (2009). Natural Language Processing with Python. O’Reilly Media Inc. Eibe, F., Hall, M. A. & Witten, I. (2016). The Weka Workbench ...
    ... the SANU - the needs and possibilities of digitization in the light of contemporary approaches (in Cyrillic)]. Kilgarriff, A., Husák, M., McAdam, K., Rundell, M. & Rychlý, P. (2008). GDEX: Automatically Finding Good Dictionary Examples in a Corpus. In E. Bernal & J. DeCesaris (eds.) Proceedings ...
    ... is valuable from the aspects of both language reception and production. Examples have different roles, some of which are mentioned by S. Atkins and M. Rundell: they can complement the definition and help the user understand the meaning of the headword/lexical unit (their informative value); they should ...

  • Production of morphological dictionaries of multi-word units using a multipurpose tool

    Ranka Stanković, Ivan Obradović, Cvetana Krstev, Duško Vitas (2011)
    The development of a comprehensive morphological dictionary of multi-word units for Serbian is a very demanding task, due to the complexity of Serbian morphology. Manual production of such a dictionary proved to be extremely time-consuming. In this paper we present a procedure that automatically produces dictionary lemmas for a given list of multi-word units. To accomplish this task the procedure relies on data in e-dictionaries of Serbian simple words, which are already well developed. We also offer an evaluation ...
    electronic dictionary, Serbian, morphology, inflection, multi-word units, noun phrases, query expansion
    ... the grant #III 47003. REFERENCES [1] B. Courtois and M. Silberztein, Dictionnaires électroniques du français. Paris: Larousse, 1990. [2] S. Paumier, Unitex 2.1 User Manual, http://www-igm.univ- mlv.fr/unitex/UnitexManual2.1.pdf, 2011. [3] M. Silberztein, “Nooj: A Linguistic Annotation System for ...
    ... by one or more equa- tions of the type Grammatical feature=value. In that case a specific form of a token is needed. In our example a token <$3:Gen=m;Nb=s;Case=4> from the lower part of the graph means that the masculine gender, singular and accusative form of the third token — the noun zvezda — is ...
    ... CflxGroup = ‘AC A3XN ’> m’ />

  • Navigacija budućnosti: poslovni rizici i prilike u rudarskoj industriji

    Petar Marković, Dejan Stevanović, Mirjana Banković, Vuk Lazić (2024)
    Sektor rudarstva i metalurgije se globalno suočava sa brzo evoluirajućim okruženjem u 2024. godini, koje karakteriše jedinstvena međusobna zavisnost rizika i prilika. Sektor je u središtu globalne energetske tranzicije, uz rastuću potražnju za kritičnim mineralnim sirovinama poput litijuma, nikla i bakra, koji su od suštinskog značaja za tehnologije obnovljive energije i električna vozila. Međutim, ova sve veća odgovornost donosi brojne izazove, uključujući pojačanu pažnju na ekološke, društvene i upravljačke (ESG) faktore, fizičke i tranzicione rizike uzrokovane klimatskim promenama, i ...

  • Coal homogenization stockyard sizing “Tamnava – Zapad” case study

    Božo Kolonja, Dinko Knežević, Ranka Stanković, Dejan Stevanović, Detlef Trummer (2016)
    ... permitted speed need to be taken into account. Because of risk of overheating of the electric motor, every stacker has a minimum travel speed (around 2-4 m/minute), which then restricts the minimum number of layers. This consideration should include an analysis of the stacker's operating capacity. This ...
    ... stacking coal from the "Tamnava – Zapad" pit Thus for the maximum hourly pit capacity of 5000 t and the permitted speed range of the stacker (4-20 m/min) coal can be stacked in 16 to 90 layers. For a more realistic hourly capacity, the minimum and maximum number of layers changes. For a pit rate ...
    ... at the stockyard Table 1. Comparing coal stockyard capacity utilization with 4 and 6 piles Number of packages 2 + 2 3 + 3 Total length 570 m Coal mass, total 400,000 t 375,000 t Coal mass per package 100,000 t 65,000 t Reserve 8 days 7.5 days Time per package 6 shifts 4 shifts Max ...

  • An Efficient Class of Iterative Root-Finding Methods with Applications

    Dejan Ćebić, Nebojša Ralević (2021)

  • The different approaches in seismic stratigraphy interpretation

    Dejan Radivojević (2018)
    U tekstu su prikazana dva osnovna pristupa u seizmostratigrafskoj interpretaciji. Prvi kao polaznu osnovu ima seizmičke sekcije, čija se interpretacija u kasnijoj fazi koreliše sa bušotinskim podacima. Drugi u prvoj fazi analizira podatke dobijene dubokim bušenjem koji se kasnije korelišu sa seizmičkim sekcijama. Prikazan je hronološki redosled i objašnjen postupak pri seizmostratigrafskoj interpretaciji oba pristupa. Ovakav način interpretacije omogućio je naftnim kompanijama detaljnije i preciznije sagledavanje geoloških odnosa, smanjenje rizika istraživanja i racionalnije projektovanje razradnih bušotina.
    seizmostratigrafija, istraživanje nafte i gasa, karakteristične seizmičke sekvence, seiz-mofacijalna analiza
    ... J. M, Seismic Stratigraphy and global changes in sea level Part 9: seismic interpretation of clastic depositional facies. In: Pay- ton (Eds.), Seismic Stratigraphy: Application to Hy- drocarbon Exploration, AAPG-Mem., 26, p 165-184. Tulsa, Oklahoma, 1977. [10] Vail P. R, Mitchum, R. M. and ...
    ... Elsevier, pp 375, Amsterdam, 2007. [2] Emery D. & Myers K. J, Sequence Stratigraphy, Bla- ckwell Science, pp 297, Oxford, 2001. [3] Mitchum R. M. Jr. & Vail P. R, Seismic stratigraphy nad global changes of sea level, part 7: stratigraphic interpretation of seismic reflection patterns in ...
    ... Payton (Eds.), Seismic Stratigraphy: Application to Hydrocarbon Explo- ration, AAPG-Mem., 26, p 135-144. Tulsa, Oklaho- ma, 1977. [4] Mitchum R. M, Vail P. R. & Thompson S, Seismic stratigraphic and global changes in sealevel, part 2: The depositional seqence as a basic unit for strai- graphic ...

  • Optimising in electrical energy consumption in mining plants

    Snežana Aleksandrović, Vesna Damnjanović, Ilija Jeftenić (2018)

  • Why classical sequence stratigraphy doesn't work in Pannonian basin?

    Dejan Radivojević (2018)
    basen iza ostrvskog luka, detačment, miocen, Panonski basen, riftogeneza, sekvenciona stratigrafija
    ... Sequence Stratigraphy, edited by G. D. Williams and A. Dobb, Geol. Soc. Spec. Publ., 71, 35–66,  doi:10.1144/GSL.SP.1993.071.01.03.  Sztanó, O., M. Kovač, I. Magyar, M. Šujan, L. Fodor, A. Uhrin, S. Rybar, S., G. Csillag, and L. Tokes, 2016.  Late Miocene  sedimentary  record of  the Danube  / Kisalföld Basin:  ...
    ... asin:  interregional correlation of  depositional systems, stratigraphy and structural evolution, Geologica Carpatica, 67, 6, 525–542.  ter  Borgh, M.,  Radivojević, D., Matenco,  L.,  2015.  Constraining  forcing  factors  and  relative  sea‐level  fluctuations in semi‐enclosed basins: The Late Ne ...

  • Ionothermal synthesis and crystal structure of a new organic–inorganic hybrid compound:catena-poly[bis(1-ethyl-3-methylimidazolium) [hepta-μ-bromido-pentacuprate(I)]]

    Ljiljana Karanović, Dejan Poleti, Tamara Đorđević (2014)
    A new organic-inorganic hybrid compound, catena-poly[bis(1-ethyl-3-methylimidazolium) [μ5-bromido-tri-μ3-bromido-tri-μ2-bromido-pentacuprate(I)]], {(C6H11N2)2[Cu5Br7]}n, has been obtained under ionothermal conditions from a reaction mixture containing Ba(OH)2•8H O, Cu(OH)2•2H2O, As2O5 , 1-ethyl-3-methylimidazolium bromide and distilled water. The crystal structure consists of complex [Cu5Br7]2- anions arranged in sinusoidal {[Cu5Br7]2-}n chains running along the a axis, which are surrounded by 1-ethyl-3-methylimidazolium cations. Three of the five unique Br atoms and one of the three Cu(I) atoms occupy special positions with half-occupancy (a mirror plane perpendicular to the b ...
    кристална структура, органско-неорганско хибридно једињење, бакар(I) бромид, јонотермна синтеза, 1-етил-3-метилимидазолијум бромид, Cu•••Cu интеракције

  • Against the tide: southeast to northwest shelf-edge progradation in the southeastern margin of Lake Pannon, Banat (Serbia and Romania)

    Dejan Radivojević, Miloš Radonjić, Lajos Tamás Katona, Imre Magyar (2022)
    In the late Neogene, the Pannonian Basin in Central Europe was filled with sediments when rivers from the Alps and Carpathians shed their sediment load into Lake Pannon. The most powerful source-to-sink system was that of the paleo-Danube, transporting sediments from the NW as far as the southeastern part of the lake. In the southeastern margin of the basin, however, local sedimentary systems worked in the opposite direction, against the “tide” of the prevailing N to S sediment transport. ...
    General Earth and Planetary Sciences

  • Filling of dolines with aeolian sediments in the high-mountain karst of the Dinarides (Mt. Durmitor, Montenegro)

    Mirela Djurović, Violeta Gajić, Predrag Djurović (2022)
    Filling of dolines with aeolian sediments, one of the less frequently described ways in which they are filled, is analysed in the present study on an example of a doline in the high-mountain karst of the Dinarides. There is a series of deep dolines on a broad ridge (about 2450 m a.s.l.) on Mt. Durmitor (Montenegro) in the southeastern part of the Dinarides. The accumulation of very fine-grained sand that almost completely fills one of the dolines was analysed. ...
    Doline, Zapuna, Eolski sedimenti, Karst, Dinaridi, Crna Gora