Levinson, A. (1955). The mentally retarded child: A guide for parents; prepared under auspices of the Dr. Julian D. Levinson Research Foundation. George Allen & Unwin.
Lua i Stíl Chicago (17ú heag.)Levinson, Abraham. The Mentally Retarded Child: A Guide for Parents; Prepared Under Auspices of the Dr. Julian D. Levinson Research Foundation. London: George Allen & Unwin, 1955.
Lua MLA (8ú heag.)Levinson, Abraham. The Mentally Retarded Child: A Guide for Parents; Prepared Under Auspices of the Dr. Julian D. Levinson Research Foundation. George Allen & Unwin, 1955.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.