- Extraction of oil from Jordanian Attarat oil shaleTiikma, Laine; Johannes, Ille; Luik, Hans; Lepp, Ardi; Šarajeva, GalinaOil shale2015 / p. 218-239 : ill http://dx.doi.org/10.3176/oil.2015.3.03 https://artiklid.elnet.ee/record=b2740510*est
- Low temperature pyrolysis of graptolite argillite (Dictyonema shale) in autoclavesŠarajeva, Galina; Tiikma, Laine; Luik, Hans; Johannes, IlleInternational journal of engineering research and applications2015 / p. 16-22 : ill http://www.ijera.com/papers/Vol5_issue11/Part%20-%201/D511011622.pdf
- Thermal extraction of oil from a Utah Green River (USA) oil shale in autoclavesJohannes, Ille; Tiikma, Laine; Luik, Hans; Šarajeva, GalinaInternational journal of engineering and applied sciences (EAAS)2015 / p. 23-35 : ill http://eaas-journal.org/survey/userfiles/files/v6i504%20Oil%20Shale%20and%20Renewables%20Research(1).pdf