Gaya APA

Swanson, C, P., Tandberg, E. (NULL). Solar Activity . Waltham:: Waltham: Blaisdell; 1967.

Gaya MLA

Swanson, Carl, P.., Tandberg, Einar. "Solar Activity". Waltham:: Waltham: Blaisdell; 1967, NULL. Text.