Coombs, P. -., Evans, M., & Hardy, P. E. (2012). Pastel painting: Step-by-step.
Chicago Style aipamenaCoombs, Peter -2007, Margaret Evans, and Paul E. Hardy. Pastel Painting: Step-by-step. 2012.
MLA aipamenaCoombs, Peter -2007, et al. Pastel Painting: Step-by-step. 2012.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.