APA (7e ed.) Bronvermelding

Não informado. (1988). 21st. Century science & technology. 21st. Century Science Associates.

Chicago (17e ed.) Bronvermelding

Não informado. 21st. Century Science & Technology. Washington: 21st. Century Science Associates, 1988.

MLA (8e ed.) Bronvermelding

Não informado. 21st. Century Science & Technology. 21st. Century Science Associates, 1988.

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