Gaya APA

B.V., S, I, P, M. (1976). Coal Exploration and Mining Manual Part I : Intoduction to Coal Geology . : Shell Internationale Petroleum Maatschappu B.V..

Gaya MLA

B.V., Shell, Internationale, Petroleum, Maatschappu. "Coal Exploration and Mining Manual Part I : Intoduction to Coal Geology". : Shell Internationale Petroleum Maatschappu B.V., 1976. Text.