APA (7e ed.) Bronvermelding

Não informado. (1939). Quarterly Bulletin on Solar Activity. International Astronomical Union.

Chicago (17e ed.) Bronvermelding

Não informado. Quarterly Bulletin on Solar Activity. Zurich, Suíça: International Astronomical Union, 1939.

MLA (8e ed.) Bronvermelding

Não informado. Quarterly Bulletin on Solar Activity. International Astronomical Union, 1939.

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