Hydrogenation of Estonian oil shale and shale oil
Kogerman, Paul
;
Kopvillem, Jaan
1932
https://www.ester.ee/record=b2170142*est
https://digikogu.taltech.ee/et/Item/b761323c-f805-4666-bdd7-3a32f1072514
On the chemistry of the Estonian oil shale "kukersite" : a monograph
Kogerman, Paul
1931
https://www.ester.ee/record=b4272601*est
Physical properties of Estonian shale oils
Kogerman, Paul
;
Kõll, A.
1930
https://www.ester.ee/record=b1455301*est