Cita APA (7th ed.)
Gregory, A., Hartley, J., & Lewis, D. (1969). Basic statistics. Methuen.
Cita Chicago (17th ed.)
Gregory, A.H, J.R Hartley, i D.G Lewis. Basic Statistics. London: Methuen, 1969.
Cita MLA (9th ed.)
Gregory, A.H, et al. Basic Statistics. Methuen, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.