APA

Pratchett T., Stewart I. & Cohen J. (2002). The Science of Discworld. London: Ebury Press.

Chicago

Pratchett T, Stewart I and Cohen J. 2002. The Science of Discworld. London: Ebury Press.

Harvard

Pratchett T., Stewart I. and Cohen J. (2002). The Science of Discworld. London: Ebury Press.

MLA

Pratchett T, Stewart I and Cohen J. The Science of Discworld. London: Ebury Press. 2002.