Rock, D. (2009). Your Brain at Work: Strategies for Overcoming Distraction, Regaining Focus, and Working Smarter All Day Long. Harper Business.
37
Bahrick, H. P., Bahrick, L. E., Bahrick, A. S. & Bahrick, P. E. (1993). «Maintenance of Foreign Language Vocabulary and the Spacing Effect», Psychological Science, vol. 4, no. 5 (pp. 316–321).