Lewis, R. F. (1970). Planning and control for profit. Heinmann.
Chicago Style aipamenaLewis, Ralph F. Planning and Control for Profit. London: Heinmann, 1970.
MLA aipamenaLewis, Ralph F. Planning and Control for Profit. Heinmann, 1970.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.