1. Warren H. C. , History of Association Psychology.
2. Tests of Perseveration. 1. Their Relation to Character;Pinard;Brit. Journ. Psychol.,1932
3. Müller G. E. , and Pilzecker A. , “Experimentelle Beiträge zur Lehre vom Gedächtniss”, Zeitschr. f. Psychol., 1900, Erg. 1.
4. Perseveration;Lankes;Brit. Journ. Psychol.,1915