APA

Backeberg C., . (1950). Some results of twenty years of Cactus research / Curt Backeberg. : Cactus and Succulent Society of America.

Chicago

Backeberg Curt, . 1950. Some results of twenty years of Cactus research / Curt Backeberg. : Cactus and Succulent Society of America.

Harvard

Backeberg C., . (1950). Some results of twenty years of Cactus research / Curt Backeberg. : Cactus and Succulent Society of America.

MLA

Backeberg Curt, . Some results of twenty years of Cactus research / Curt Backeberg. : Cactus and Succulent Society of America. 1950.