MLA

Robertson, J. M. Christianity and Mythology. 2. ed., rev. and expanded. London: Watts, 1910.

APA

Robertson, J. M. (1910). Christianity and mythology. 2. ed., rev. and expanded. London: Watts.

Chicago

Robertson, J. M. Christianity and Mythology. 2. ed., rev. and expanded. London: Watts, 1910.