Bahrick, H.P., & Phelps, E.A. (1987). Retention of Spanish vocabulary over 8 years. Journal of Experimental Psychology: Learning, Memory, and Cognition, 13, 149-56.

Bahrick, H.P., & Phelps, E.A. (1987).  Retention of Spanish vocabulary over 8 years.  Journal of Experimental Psychology: Learning, Memory, and Cognition, 13, 149-56.