Perrin, R. (1971). Focus the future: An introduction to long range corporate planning. Management.
Chicago Style aipamenaPerrin, Robert. Focus the Future: An Introduction to Long Range Corporate Planning. London: Management, 1971.
MLA aipamenaPerrin, Robert. Focus the Future: An Introduction to Long Range Corporate Planning. Management, 1971.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.