Ilmar Öpik, member of the Estonian Academy of Sciences
Ots, Arvo
Oil shale
2002
/
p. 181-185 : phot
Ilmar Öpik, member of the Estonian Academy of Sciences
Ots, Arvo
Ilmar Öpik : personaalnimestik
1994
/
lk. 7-10, 19-25