APA (7e ed.) Bronvermelding

Não informado. (1961). Building Materials. Leonard Hill Technical Group.

Chicago (17e ed.) Bronvermelding

Não informado. Building Materials. London: Leonard Hill Technical Group, 1961.

MLA (8e ed.) Bronvermelding

Não informado. Building Materials. Leonard Hill Technical Group, 1961.

Let op: Deze citaties zijn niet altijd 100% accuraat.