1. Kleinkinder Tests;Bühler,1932
2. Maternal deprivation: a critical review of the literature;Casler;Soc. Res. Child Develpm.,1961
3. Harlow, H. & Harlow, M. (1964), The effects of early social deprivation on primates. Read and discussed by Dr. R. Spitz at Clinique Psychiatrique de l'Université de Genève, on “Deafferentation expérimentale et Clinique.”
4. Infant care and personality;Orlansky;Psychol. Bull.,1949
5. The smiling response: I. Quantification, methodology, and natural history;Polak;J. Nerv. Ment. Dis.,1964