APA (7th ed.) Zitazioa

Christensen,Howard B. (1977). Statistics step by step. Houghton Mifflin.

Chicago Style (17th ed.) Zitazioa

Christensen,Howard B. Statistics Step by Step. Atlanta: Houghton Mifflin, 1977.

MLA (9th ed.) Zitazioa

Christensen,Howard B. Statistics Step by Step. Houghton Mifflin, 1977.