APA (7e ed.) Bronvermelding

Grorge, D., & Mallery, P. (2014). IBM statistics 21 step by step: A simple guide and reference (13th ed.). Pearson Education.

Chicago (17e ed.) Bronvermelding

Grorge, Darren, en Paul Mallery. IBM Statistics 21 Step by Step: A Simple Guide and Reference. 13th ed. U.S.A.: Pearson Education, 2014.

MLA (8e ed.) Bronvermelding

Grorge, Darren, en Paul Mallery. IBM Statistics 21 Step by Step: A Simple Guide and Reference. 13th ed. Pearson Education, 2014.