Gaya APA

Leffler, W, L. (2010). Petroleum refining in nontechnical language 9 : Distilate and residual fuels, asphalt (4). New York: PennWell B.

Gaya MLA

Leffler, William, L.. "Petroleum refining in nontechnical language 9 : Distilate and residual fuels, asphalt". 4 New York: PennWell B, 2010. Multimedia.