Amount of water in abandoned oil shale mines depending on mining technology in EstoniaKaru, Veiko9th International Symposium "Topical problems in the field of electrical and power engineering". Doctoral school of energy and geotechnology. II : Pärnu, Estonia, June 14-19, 20102010 / p. 83-85 : ill https://kirjandus.geoloogia.info/en/reference/32933