Freedman, Alan
Amacom, 1995
Buku Referensi
Greenfield, Jane
Oak Knoll Press, 1998
Buku Teks
Andersen, Dines
Copenhagen: Gyldendalske Boghandel, 1907
Buku Teks
American Psychiatric Press, 1984
Buku Referensi
Harrod, Leonard Montague
England : Gower Pub, 1987,
Buku Referensi