• Detection of mine collapses with seismic methods in the Estonian oil shale mining areaOtsmaa, Merle; Soosalu, Heidi Elisabet; Valgma, Ingo12th International Symposium "Topical Problems in the Field of Electrical and Power Engineering." Doctoral School of Energy and Geotechnology II : Kuressaare, Estonia, June 11-16, 20122012 / p. 171-172 : ill