The riddle of the universe

MLA

Haeckel, Ernst, H. James Birx, and Joseph McCabe. The Riddle of the Universe. London: Watts & Co., 1946.

APA

Haeckel, E., Birx, H. James, & McCabe, J. (1946). The riddle of the universe. London: Watts & Co.

Chicago

Haeckel, Ernst, and H. James Birx. The Riddle of the Universe. Translated by Joseph McCabe. London: Watts & Co., 1946.