Jurij Kasjan
in Coral Cave, Arabika, 2019
Born	(1961-05-06) 6 May 1961 Snjatin, Ukraine
Alma mater	Ivano-Frankivsk National Technical University of Oil and Gas
Years active	1978–present
Known for	speleology, deep cave projects
Spouses	Antonina Kasjan ​ ​ (m. 1983⁠–⁠1989)​ Julija Timoševskaja ​ ​ (m. 1991⁠–⁠2002)​ Katerina Medvedeva ​ ​ (m. 2003⁠–⁠2005)​ Natalija Ščuka ​ (m. 2009⁠–⁠2011)​ Zinaida Kasjan ​ (m. 2011)​
Children	Anastasija, Sergej, Denis, Evgenij, Anatolij

Jurij Mihajlovič Kasjan (also spelled Yuriy Mikhailovich Kasyan, Iurii Mihajlovič Kasian, pron. Yooreey Mikhaylovich Kasyan; Юрий Михайлович Касьян; born 6 May 1961 in Snjatin^[1]) is a Ukrainian speleologist, most known for his work in cave exploration, especially as the Call of the Abyss research project coordinator.^[2] He was heading the speleological expeditions to caves of the Arabika massif in Abkhazia and, with Aleksandr Klimčuk, to Aladaglar massif in Turkey. Some of the world's deepest caves were explored,^[2][3] including the first cave, deeper than 2,000 m, the Krubera-Voronja Cave.^[4][5]

Early life, education and career

Kasjan was born in Snjatin, a small town in Western Ukraine, in the Ivano-Frankivsk Oblast (Province), to the north of Moldova. His father Mihail Jurjevič Kasjan was chairman of the District Council of the Sports Society "Grain Ear", which promoted athletic development in the countryside, and his mother Nelja Dmitrievna was a statistician in the accounting department of the district party committee. After high school in Snjatin where he also pursued swimming and freestyle wrestling he graduated (1984) in geology at the Ivano-Frankivsk National Technical University of Oil and Gas in the province capital Ivano-Frankivsk. After graduation he moved to Poltava for a job in the regional branch of the All-Union Research and Design Institute for Explosive Geophysical Survey Methods.^[6] Kasjan continued as instructor at the Poltava regional center of education in tourism and local history^[7] and from there moved on to a career in industrial rope access.^[8]

Kasjan at the entrance of the Krubera-Voronja cave in 2016

Speleology

In the autumn of 1978, at the beginning of geology study in Ivano-Frankivsk, there were 3 available extra-curricular courses: in tourism, rock climbing and speleology. From the latter two Kasjan chose speleology as the closest to geology and joined the Ivano-Frankivsk speleo club Протей [Proteus].^[9] He stayed till 1984, since 1981 he was its chairman.^[10][11] In 1984 he founded the Poltava speleoclub "Poltava-speleo", which he led until 2003.^[12] In 2004 he joined the Kiev speleoclub; for several years he was the head of its speleo school, he is a longtime member of the club board.^[13]

In 1992 Kasjan was one of the founding members of the Ukrainian Speleological Association (UkrSA).^[14][15] As of April 2019 he is the vice-president of the UkrSA; he served as president in the years 1998 - 2001 and 2006 - 2007.^[15] Since 2003 he is an honorary member of the UkrSA,^[14] in 1996 and 2012 Kasjan was the recipient of the UkrSa Diploma for Outstanding Achievements.^[16]

He is the coordinator of the Training and Methodological Commission of the UkrSA, MIPKAR and “Call of the Abyss” projects, head of the UkrSA Cave Rescue Team.^[14]

From 1978 to 1998 Kasjan's caving activity was mostly devoted to caves of Western Ukraine and the Crimea, such as Gvozdetsky abyss, Liu-Khosar shaft, Shaft of the lost ones and discovery and mapping of over 1,5 km long Poltavskiy branch of the labyrinthine Mlinki cave.^[12][17] He initiated a program of marking and revising the caves of the Karabi plateau in the Crimea (1998).^[12]

From 1998 Kasjan participated in several international caving expeditions, to Arabika massif in Abkhazia (as a leader since 1999), to Skalarjevo brezno cave on Mt. Kanin in Slovenia^[18] and Aladaglar mountain range in Turkey as the leader of operations in the cave.

Cavers are known for their superstition,^[19] and Kasjan was never tempted to estimate expedition potential in advance:

Openly talking about cave depth (you are going to achieve) is a very bad sign. If you think that you will break the record and take too much equipment with you, the cave will get scared and she will stop you.^[19]

Top three Ortobalagan caves, connected to Kasjan's work in the past 20 years

Arabika Caves

Kasjan's most important achievements are connected to exploration of a cave system above the eastern coast of the Black Sea, in the Ortobalagan valley in Abkhazia.^[20][21] He was leading the following expeditions, nearly always organized by the Ukrainian Speleological Association:

• 1999 August: the expedition's second team, trying to get an upper entrance to Arabika cave system, explored the previously disregarded windows in the shafts of Krubera-Voronja cave (-340 m at the time). One of them, at -230 m, continued to -700 m.^[22][23]
• 2000
  • August: the second team reached -1,200 m in Krubera-Voronja.^[24][23]
  • September: exploration continued to -1,410 m.^[25]
• 2001
  • December (2000) - January: - windows at - 1,350 meters led to a deeper passage at - 1,430 meters. In it a side passage at -1,420 m continued to -1,710 meters, world depth record,^[26] for the first time in a cave outside Western Europe.^[27]
  • August: explorations in the lower part (1,420 m -1,710 m);^[23] a siphon at -1,650 was dived.^[28]
• 2004 October: siphon bypass produced a descent to -2,080 meters. Another world cave depth record and Kasjan was the first caver to set foot deeper than 2,000 m.^[29][30]
• 2005
  • February: Kvitočka siphon in the Main branch of Krubera-Voronja cave was dived through and the depth of -1,980 m was reached.^[28][31]
  • October: 4 teams worked in the cave but had to stop because of flooding on 17 October.^[32]
• 2006 August: world cave depth record of 2,158 m was achieved by the diver Gennadij Samohin in the "Dva Kapitana" siphon. For the first time all the expedition garbage (excluding body waste) was brought back to surface.^[33]
• 2007 August - September: G. Samohin moved the world cave depth record to -2,191 m in the same siphon. For the first time only electric illumination was used in the cave.^[34]
• 2008 August: works continued in the main branch of the cave and in Nekujbiševskaja branch, as well as in the cave Вентилятор [Ventilation Fan].^[35]
• 2009 August - September: two teams, the second headed by Aidas Gudaitis from Lithuania, worked in Krubera-Voronja, Kujbiševskaja, Detskaja and Silver Prince caves. Temperature and pressure loggers were installed at the bottom of the cave. Radiation levels were measured in all the caves. All readings but one (in Kujbiševskaja cave at -500m) were within normal limits. There were issues with body feces contaminated water which led to serious gastrointestinal problems of one caver. The decision was made to store, in the future, all body waste in special containers and bring it back to surface.^[36]
• 2010 August - September: exploration continued in the Nekujbiševskaja branch of the cave. It was prolonged by 600 m, 2 siphons were dived.^[37]
• 2011 September: in Nekujbiševskaja branch of Krubera-Voronja the siphon Koljučka (Thorn) at 1,558 m was free dived after a drawdown, digging in a connection passage to Kujbiševskaja cave was continued. Martel cave (entrance at 2,316 m a.s.l.) was deepened to 95 m, it ends in a narrow meander with strong air current.^[38][39]
• 2012 July–August: G. Samohin corrected the world cave depth record to -2,196 m in the "Dva Kapitana" siphon of Krubera-Voronja. Martel cave depth was moved to 135 m.^[40]
• 2013 July–August: cave fauna was collected in Krubera-Voronja. Gennadij Samohin caught a few crustaceans in the "Dva Kapitana" siphon, fish traps produced no results. Martel cave was slightly prolonged, strong roar of wind follows. Works began in Berčilskaja (pron. Berchilskaya) cave (2,430 m a.s.l., -500 m), a possible higher entrance to Krubera.^[41]
• 2014 August: Amber siphon in Krubera-Voronja was dived through; the path to historical bottom at -340 m was cleared. Top tight passages in Berčilskaja were widened.^[42] An expedition of MSU Speleo Club connected Krubera-Voronja with Arbaika cave and the total depth reached 2,199 m.^[43]
• 2015 August: narrows in Berčilskaja cave, at that time 500 m deep, were cleared till the depth of 400 m.^[44]
• 2016 July–August: at the historical bottom in Krubera-Voronja a series of shafts led back to the main branch of the cave. Berčilskaja - a new bottom was reached at -630 m.^[45]
• 2017 August: In Krubera-Voronja 60 m of a large tunnel in the siphon at -1,650 m was dived. In Berčilskaja depth of -770 was reached and a better survey was made. The main direction of new parts is south, away from Krubera-Voronja. Connection will have to be searched elsewhere.^[46]
• 2018 August: digging in Berčilskaja cave was conducted, in most lucrative places for connection with Krubera-Voronja, at -480 m and at -650 m (Old School hall).^[47]

His right hand in most of these projects was Russian cave diver from Simferopol, Gennadij Samohin; as of July 2019 cavers from 20 countries have participated in the list (sorted in descending order by the number of expeditions - given after the country name if exceeding 1): Ukraine (21), Russia (14), Israel (8), United States (4), Bulgaria (3), Lithuania (3), Poland (2), Spain (2), United Kingdom (2), Belarus, Belgium, Britain, France, Iran, Ireland, Italy, Lebanon, Moldova and Turkey.^{[48][45][46][47][4][49][50][28]}


Water is probably the most picturesque cave element: Maša Plotnikova in Krubera-Voronja cave, at -1,340 m, 2007, by J. Kasjan

Aladaglar Caves

Kasjan also made a major contribution to exploration of caves in the Aladaglar mountain ridge above the southern coast of Anatolia in Turkey, in the framework of the Call of the Abyss project. From 2002 to 2008 over 150 new caves were examined in the area,^[51] most notably Kuzgun cave, discovered in 2003, explored 400 m deep and in 2004 to its final (as of 2019) depth of 1400 m.^[3] In 2005, 2008 and 2013 three caves in the vicinity which could lead to greater depth were examined, 900 m deep side branch in Kuzgun was explored and engineering works at the cave bottom, which would stabilize loose collapse, were undertaken.^[51] In 2018 and 2019 Kasjan lead expeditions to new caves in the neighbouring area, also as part of the project.^[52][53]

Film, photography, journalism

Kasjan documented the underground explorations in which he participated in over 100 short films.^[54] His photographs, especially from the Krubera-Voronja cave were published in several national and international journals,^[55][56] books^[57][58] such as The Darkness Beckons, and other publications, including the official cave photo site of the Ukrainian Speleological Association.^[59] He was a juror in international cave photography competitions.^[60][61] Since 2004 Kasjan is the editor of the Ukrainian speleo journal Свет [Light].^[62][63][14]

References

1. ↑ "Вся Украина - жители" [All Ukraine - Inhabitants] (in Russian). Retrieved 18 March 2019.
2. 1 2 "Call of the Abbys / Research Project". Ukrainian Speleological Association. Retrieved 18 March 2019.
3. 1 2 Klimchouk, Alexander; Nazik, Lutfi; Bayari, Serdar; Tork, Koray; Kasyan, Yury (2 July 2013). "Kuzgun Cave and its Context: the first super-deep cave in the Aladaglar Massif, Turkey". Retrieved 12 March 2019.
4. 1 2 Connor, Aileen; Macnamara, Stephen (2012). "Krubera-Voronja Expedition Report 2012" (PDF). Speleological Union of Ireland. Retrieved 22 March 2019.
5. ↑ Chala, Мariya (13 May 2016). "Спелеолог шукає, де глибше. Франківець Юрій Касьян першим у світі пройшов глибину понад 2000 м" [The caver explores where it goes deeper. Ivano-Frankivsk Graduate Jurij Kasjan was the first in the world to go beyond 2000 m] (in Ukrainian). Репортер / Reporter. Retrieved 22 March 2019.
6. ↑ Merkulov, Alexander. "ВНИПИвзрывгеофизика: история создания, достижения, перспективы развития" [VNIPIexplosovegeophysics: History of Formation, Achievements and Development Prospects] (in Russian). Retrieved 4 April 2019.
7. ↑ "Історія становлення та розвитку дитячо-юнацького туризму і краєзнавства на Полтавщині" [History of formation and development of children's and youth tourism and local lore in Poltava region] (in Ukrainian). Retrieved 4 April 2019.
8. ↑ "Удаление и обрезка деревьев в Киеве и области / технически сложные и не стандартные высотные работы" [Removal and pruning of trees in Kiev and the region / technically complex and non-standard high-altitude work] (in Russian). Retrieved 4 April 2019.
9. ↑ Kasjan, Jurij. "Личное снаряжение вертикальщика" [Personal Equipment of the (Vertical Cave) Climber] (in Russian). Ukrainian Speleological Association. Retrieved 22 March 2019.
10. ↑ "Спелео клуб Протей" [Speleo Club Proteus] (in Russian). Facebook. 2018. Retrieved 13 April 2019.
11. ↑ Kasjan, Jurij (26 December 2014). "50 лет Киевской спелеологии" [50 Years of Speleology in Kiev] (in Russian). Киевский спелеологический клуб / Kiev Speleo Club. Retrieved 12 April 2019.
12. 1 2 3 Dublyanskiy, Viktor Nikolaevich (2005). История украинской спелеологии [The History of Ukrainian Speleology] (PDF). Perm, Simferopol: Пермский государственный университет / Perm State University, Таврический национальный университет имени В. И. Вернадского / Tavrida National V.I. Vernadsky University. p. 111. Retrieved 24 March 2019.
13. ↑ "Kyiv Speleological Club". Ukrainian Speleological Association. Retrieved 24 March 2019.
14. 1 2 3 4 "Касьян Юрий Михайлович" [Jurij Mikhailovič Kasjan] (in Russian). Ukrainian Speleological Association. Retrieved 18 March 2019.
15. 1 2 "UkrSA Presidents". Ukrainian Speleological Association. Retrieved 18 March 2019.
16. ↑ "Laureates of Diploma "For Outstanding Achievements"". Ukrainian Speleological Association. 2017. Retrieved 16 April 2019.
17. ↑ Ziemels, Jurij; Snigur, Volodimir (2012). Печера Млинки. Печера Угриньська [Mlynky Cave. Ugrinskaya Cave] (in Ukrainian). Українська спелеологічна асоціація, Тернопілський клуб спелеологів «Подилля», Чортківський клуб спелеологів «Кристал» [Ukrainian Speleological Association, Ternopil Speleo Club «Podillya», Chortkiv Speleo Club «Crystal». p. 176.
18. ↑ Klimčuk, Oleg; Provalov, Denis (2002). "Январь 2002: Скалярьево Брезно, Монте-Канин, Словения" [January 2002: Skalarjevo brezno Cave, Mt. Kanin, Slovenia] (in Russian). Cavex. Retrieved 17 April 2019.
19. 1 2 "Зов бездны" [Call of the Abyss] (in Russian). podrobnosti.ua. 11 January 2002. Retrieved 18 April 2019.
20. ↑ Klimchouk, Alexander (2012). "Krubera (Voronya) Cave". In White, William B.; Culver, David C. (eds.). Encyclopedia of Caves (2nd ed.). Cambridge, MA: Academic Press. pp. 423–450. ISBN 9780123838322. Retrieved 4 April 2019.
21. ↑ Klimchouk, Alexander. "Call of the Abyss — World's Deepest Cave". National Geographic. Archived from the original on November 26, 2019. Retrieved 4 April 2019.
22. ↑ Timoshevskaya, Yulia (1999). "Call of the Abyss. Arabika, 1999". Ukrainian Speleological Association. Retrieved 5 April 2019.
23. 1 2 3 Valdai, Mishail (18 September 2016). "Пещера Крубера-Воронья (Абхазия) - самая глубокая из известных пещер в мире" [Krubera-Voronya Cave (Abkhazia) - the Deepest Known Cave in the World] (in Russian). LiveInternet.Ru. Retrieved 15 April 2019.
24. ↑ Timoshevskaya, Yulia (2000). "Call of the Abyss. Arabika, 2000". Ukrainian Speleological Association. Retrieved 5 April 2019.
25. ↑ Klimchouk, Alexander; Kasjan, Yuri (2001). "In a search for the route to 2000 meters depth: The Deepest Cave in the World in the Arabika Massif, Western Caucasus" (PDF). Caves & Caving (91): 34–41. Archived from the original (PDF) on 8 May 2018. Retrieved 15 April 2019.
26. ↑ Provalov, Denis; Grišina, Evgenija; Skljarenko, Dmitrij (24 March 2001). "Экспедиция "Крубера-Воронья - 2001"" [Expedition "Krubera-Voronya - 2001"] (in Russian). Mountain.RU. Retrieved 9 April 2019.
27. ↑ "Krubera (Voronja) Cave: the first 2000m+ cave on Earth". UIS Commission on Karst Hydrology and Speleogenesis, IAH Commission on Karst Hydrology. 2012. Retrieved 13 April 2019.
28. 1 2 3 Kasyan, Yuriy; Shturma, Oleksandra (January 3, 2017). "17 Siphons of Krubera-Voronya Cave". Ukrainian Speleological Association. Retrieved 5 April 2019.
29. ↑ Klimčuk, Aleksandr (31 October 2004). "Пещера Крубера ? 2080 метров" [Krubera Cave ? 2080 meters] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
30. ↑ Klimchouk, Alexander (19 April 2005). "Call of the Abyss-World's Deepest Cave". National Geographic. Archived from the original on November 26, 2019. Retrieved 5 April 2019.
31. ↑ Kasjan, Jurij (19 March 2005). "Результаты экспедиции УСА в п. Крубера" [The Results of the UkrSA Expedition to Krubera Cave] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
32. ↑ Kasjan, Jurij (5 November 2005). "Экспедиция УСА в Крубера-Воронью" [UkrSA Expedition to Krubera-Voronya] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
33. ↑ Kasjan, Jurij (23 September 2006). "Экспедиция УСА в пещеру Крубера-Воронью" [UkrSA Expedition to Krubera-Voronya Cave] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
34. ↑ Kasjan, Jurij (20 September 2007). "Результаты экспедиции УСА в пещеру Крубера-Воронья" [The Results of the UkrSA Expedition to Krubera-Voronya Cave] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
35. ↑ Kasjan, Jurij (22 September 2008). "Итоги экспедиции УСА в пещеру Крубера-Воронья" [Summary of the UkrSA Expedition to Krubera-Voronya Cave] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
36. ↑ Kasjan, Jurij; Gudaitis, Aidas (10 September 2009). "Результаты экспедиции УСА в пещеры долины Орто-Балаган (Арабика, Абхазия)" [The Results of the UkrSA expedition to the Orto-Balagan Valley Caves (Arabika, Abkhazia)] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
37. ↑ Kasjan, Jurij (12 September 2010). "Экспедиция УСА в пещеру Крубера-Воронья" [UkrSA Expedition to Krubera-Voronya Cave] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
38. ↑ Kasjan, Jurij (3 September 2011). "Экспедиция УСА в пещеры Орто Балагана (Арабика, Абхазия)" [UkrSA expedition to the Orto-Balagan Valley Caves (Arabika, Abkhazia)] (in Russian). Cavers Mailing List. Retrieved 9 April 2019.
39. ↑ Kasjan, Jurij (2011). "UkrSA Expedition to the Valley Ortobalagan Caves Results" (in Russian). Ukrainian Speleological Association. Retrieved 5 April 2019.
40. ↑ Kasjan, Jurij (2012). "Call of the Abyss 2012. Photo Report" (in Russian). Ukrainian Speleological Association. Retrieved 5 April 2019.
41. ↑ Kasjan, Jurij (2013). "Results of Ukrsa Expedition to the Valley Orthobalagan Caves (Arabika, Abkhazia)" (in Russian). Ukrainian Speleological Association. Retrieved 5 April 2019.
42. ↑ Kasyan, Yuriy (2014). "Call of the Abyss. Arabika, 2014". Ukrainian Speleological Association. Retrieved 5 April 2019.
43. ↑ Šuvalov, Andrej (21 August 2014). "Экспедиция КС МГУ в п. Крубера-Воронья" [Speleo Club MSU Expedition to Krubera-Voronya Cave] (in Russian). Retrieved 18 April 2019.
44. ↑ Kasyan, Yuriy; Sukhoviy, Helen (2015). "Call of the Abyss. Arabika, 2015". Ukrainian Speleological Association. Retrieved 5 April 2019.
45. 1 2 Kovalev, Roman; Sarvarova, Ekaterina (September 2016). "Arabika 2016 or 5000 km from Siberia and 2 km Underground". Ukrainian Speleological Association. Retrieved 5 April 2019.
46. 1 2 Kasyan, Yuri (2017). "Call of the Abyss. Arabika, 2017". Ukrainian Speleological Association. Retrieved 5 April 2019.
47. 1 2 Kasjan, Jurij (31 August 2018). "Пещера Берчильская 2018" [Berchilskaya Cave 2018] (in Russian). Retrieved 11 August 2019.
48. ↑ "Some statistics and chronology. Expeditions to Krubera-Voronya cave under the auspices of the Ukrainian Speleological Association since 1999". 2015. Retrieved 13 April 2019.
49. ↑ Krotowski, Tomasz (December 2015). "Pierwsi na dnie świata" [The First at the Bottom of the World] (in Polish). Przegląd Pożarniczy. Retrieved 21 March 2019.
50. ↑ Ambrus, Gergely; Adamkó, Péter (2 December 2016). "Inverse Everest". Földgömb (in Hungarian). Retrieved 26 March 2019.
51. 1 2 Samokhin, Gennady. "Пещера Кузгун, массив Аладаглар, восточный Тавр, Турция, 2013" [Kuzgun Cave, Aladaglar Massif, Eastern Taurus, Turkey, 2013] (in Russian). Ukrainian Speleological Association. Retrieved 28 July 2019.
52. ↑ Kasjan, Jurij. "Зов бездны. Аладаглар 2018" [Call of the Abyss, Aladaglar 2018] (in Russian). Ukrainian Speleological Association. Retrieved 28 July 2019.
53. ↑ Kasjan, Jurij. "Зов бездны. Аладаглар 2019" [Call of the Abyss, Aladaglar 2019] (in Russian). Ukrainian Speleological Association. Retrieved 28 July 2019.
54. ↑ Kasjan, Jurij. "Jurij Kasjan Videos". You Tube. Retrieved 18 March 2019.
55. ↑ Elor, Gilly (March 2019). "Krubera-Voronya 2017". NSS News. 77 (3): 4–9. Retrieved 30 March 2019.
56. ↑ Samokhin, Gennady; Bizyukin, Andrey (January 3, 2017). "Voronya Cave: Diving Deeper into the Deepest Cave on Earth". X-Ray Mag / International Dive Magazine. Retrieved 21 March 2019.
57. ↑ Farr, Martyn (2017). The Darkness Beckons / The history and development of world cave diving. Sheffield, UK: Vertebrate Publishing. p. 416. Retrieved 31 March 2019.
58. ↑ Giorgobiani, Liana; Ninikashvili, Tamar; Liparteliani, Irma; Dvalashvili, Giorgi; Noneshvili, Alexandr (2017). 100 памятников природы и материальной культуры Грузии [100 Monuments of Nature and Material Culture in Georgia] (in Russian). Tbilisi, Georgia: KLIO Publishing House. p. 128.
59. ↑ Kasjan, Jurij; Plotnikova, Marija; Medvedeva, Katerina; Lata, Evgenij (2011). "Глубочайшая пещера мира Крубера-Воронья в фотографиях" [The World's Deepest Cave Krubera-Voronya in Photos] (in Russian). Ukrainian Speleological Association. Retrieved 23 March 2019.
60. ↑ "The winners of the photocontest The Speleo Photo of the Year 2009". Caving club "Ænigma". 2009. Retrieved 20 March 2019.
61. ↑ "2011 Speleo Photo of the Year Winners Announced". Caving News. 18 February 2012. Retrieved 10 March 2019.
62. ↑ "2017 - Касьян Юрий Михайлович" [2017 - Jurij Mihailovič Kasjan]. Ukrainian Speleological Association. Retrieved 26 March 2019.
63. ↑ ""СВЕТ" - ЖУРНАЛ УКРАИНСКОЙ СПЕЛЕОЛОГИЧЕСКОЙ АССОЦИАЦИИ" ["Light" - Ukrainian Speleological Association Journal]. Ukrainian Speleological Association. Retrieved 26 March 2019.