Reutersward, C. W. P., & Hjertstrand, A. (1961). XIth International Astronautical Congress, Stockholm 1960 : =: XI. Internationaler Astronautischer Kongress = XIe Congres International d'Astronautique / : proceedings =. Wien: Springer-Verlag.
Παραπομπή Chicago StyleReutersward, Carl W. P., and Ake Hjertstrand. XIth International Astronautical Congress, Stockholm 1960 : =: XI. Internationaler Astronautischer Kongress = XIe Congres International D'Astronautique / : Proceedings =. Wien: Springer-Verlag, 1961.
Παραπομπή MLAReutersward, Carl W. P., and Ake Hjertstrand. XIth International Astronautical Congress, Stockholm 1960 : =: XI. Internationaler Astronautischer Kongress = XIe Congres International D'Astronautique / : Proceedings =. Wien: Springer-Verlag, 1961.