Appell, J. (2004). Nonlinear spectral theory. Walter de Gruyter.
Chicago Style aipamenaAppell, Jurgen. Nonlinear Spectral Theory. New York: Walter de Gruyter, 2004.
MLA aipamenaAppell, Jurgen. Nonlinear Spectral Theory. Walter de Gruyter, 2004.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.