APA (7e ed.) Bronvermelding

Não informado. (1921). Bulletin of the Astronomical Institutes of the Netherlands. Astronomical Institutes of the Netherlands.

Chicago (17e ed.) Bronvermelding

Não informado. Bulletin of the Astronomical Institutes of the Netherlands. Amsterdam: Astronomical Institutes of the Netherlands, 1921.

MLA (8e ed.) Bronvermelding

Não informado. Bulletin of the Astronomical Institutes of the Netherlands. Astronomical Institutes of the Netherlands, 1921.

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