APA (7th ed.) Citation

Observatoire de Marseille & European Southern Observatory. (1970). Astronomy & astrophysics. European Southern Observatory and Observatoire de Marseille.

Chicago Style (17th ed.) Citation

Observatoire de Marseille and European Southern Observatory. Astronomy & Astrophysics. [Hamburg?]: European Southern Observatory and Observatoire de Marseille, 1970.

MLA (9th ed.) Citation

Observatoire de Marseille and European Southern Observatory. Astronomy & Astrophysics. European Southern Observatory and Observatoire de Marseille, 1970.