1. Ebbinghaus, M. (1885) Über das Gedächtnis, p. 1, K. Buehler.
2. Experimentelle beitrage zur lehre vom gedachtnis;Müller;Z. Psychol.,1900
3. Les Maladies de la Memoire;Ribot,1881
4. Perseverative neural processes and consolidation of the memory trace;Glickman;Psychol. Bull.,1961
5. Time-dependent processes in memory storage;McGaugh;Science,1966