Cita APA (7th ed.)
Harrison, P. (1983). Seabirds an identification guide. Houghton mifflin company.
Cita Chicago (17th ed.)
Harrison, Peter. Seabirds an Identification Guide. Boston: Houghton mifflin company, 1983.
Cita MLA (9th ed.)
Harrison, Peter. Seabirds an Identification Guide. Houghton mifflin company, 1983.
Atenció: Aquestes cites poden no estar 100% correctes.