Cita APA (7a ed.)
Harnack, A. (1957). What is Christianity? Peter Smith Publishers.
Cita Chicago Style (17a ed.)
Harnack, Adolf. What Is Christianity? U.S.A: Peter Smith Publishers, 1957.
Cita MLA (9a ed.)
Harnack, Adolf. What Is Christianity? Peter Smith Publishers, 1957.
Precaución: Estas citas no son 100% exactas.