APA

Vassilev S. V., Eskenazy G. M. & Eskenazy G. M.Behaviour of elements and minerals during preparation and combustion of the Pernik coal, Bulgaria. : .

Chicago

Vassilev Stanislav V, Eskenazy Greta M and Eskenazy Greta M.Behaviour of elements and minerals during preparation and combustion of the Pernik coal, Bulgaria. : .

Harvard

Vassilev S. V., Eskenazy G. M. and Eskenazy G. M.Behaviour of elements and minerals during preparation and combustion of the Pernik coal, Bulgaria. : .

MLA

Vassilev Stanislav V, Eskenazy Greta M and Eskenazy Greta M.: . .