Gaya APA

Christopher, H, A, H. (1978). Geothermal energy : Its past, present and future contributions to the energy needs of man (1978). New York: New York : John Wiley & Sons, Inc.,.

Gaya MLA

Christopher, H., Armstead,, H.. "Geothermal energy : Its past, present and future contributions to the energy needs of man". 1978 New York: New York : John Wiley & Sons, Inc.,, 1978. Text.