Farnham-Diggory, Sylvia Schooling / Sylvia Farnham-Diggory . - Cambrodge : Harvard University Press, 1990 . - VII-236 p. : ill., couv. ill. en coul. ; 21 cm. - The Developing child series . Index ISBN: 9780674792722 0674792726 Source: Don du C.C.A. Universal Decimal Class. No.: 370.