Friend, G., & Zehle, S. (2004). Guide to business planning. Economist in association with Profile Books.
Chicago-viite (17. p.)Friend, Graham, ja Stefan Zehle. Guide to Business Planning. London: Economist in association with Profile Books, 2004.
MLA-viite (9. p.)Friend, Graham, ja Stefan Zehle. Guide to Business Planning. Economist in association with Profile Books, 2004.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.