Johnston, M. W. (2008). Relationship selling. McGraw-Hill/Irwin.
Chicago Style aipamenaJohnston, Mark W. Relationship Selling. McGraw-Hill/Irwin, 2008.
MLA aipamenaJohnston, Mark W. Relationship Selling. McGraw-Hill/Irwin, 2008.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.