एपीए उद्धरण

Langford, P. (1987). Concept devolopment in the secondary school. Croom Helm.

शिकागो स्टाइल उद्धरण

Langford, Peter. Concept Devolopment in the Secondary School. London: Croom Helm, 1987.

एमएलए उद्धरण

Langford, Peter. Concept Devolopment in the Secondary School. Croom Helm, 1987.