Ravenholt, A. (1968). Philippine Rock Industries, Incorporated: Grinding rock becomes a successful business venture. American Universities Field Staff.
Chicago (17e ed.) BronvermeldingRavenholt, Albert. Philippine Rock Industries, Incorporated: Grinding Rock Becomes a Successful Business Venture. [New York]: American Universities Field Staff, 1968.
MLA (9e ed.) BronvermeldingRavenholt, Albert. Philippine Rock Industries, Incorporated: Grinding Rock Becomes a Successful Business Venture. American Universities Field Staff, 1968.
Let op: Deze citaties zijn niet altijd 100% accuraat.