Gaya APA

Abbott, K, S, B, B, B. (2005). Research Design and Methods: A process approach (6th ed.). indiana university, Fort Wayne: Mc Graw Hill.

Gaya MLA

Abbott, Kenneth, S., Bordens,, Bruce, B.. "Research Design and Methods: A process approach". 6th ed. indiana university, Fort Wayne: Mc Graw Hill, 2005. Text.