Gray, D. E. (1966). Man and his physical world. D. Van Nostrand.
Cita Chicago Style (17a ed.)Gray, Dwight E. Man and His Physical World. Princeton: D. Van Nostrand, 1966.
Cita MLA (9a ed.)Gray, Dwight E. Man and His Physical World. D. Van Nostrand, 1966.
Precaución: Estas citas no son 100% exactas.