APA (7th ed.) Citation

Elkind, D. D. (1975). Programmed learning aid for cognitive development. Learning Systems.

Chicago Style (17th ed.) Citation

Elkind, David D. Programmed Learning Aid for Cognitive Development. Homewood, Ill: Learning Systems, 1975.

MLA (9th ed.) Citation

Elkind, David D. Programmed Learning Aid for Cognitive Development. Learning Systems, 1975.