Appell, J., De Pascale, E., & Vignoli, A. (2004). Nonlinear spectral theory. Walter de Gruyter.
Chicago-čujuhus (17. p.)Appell, Jürgen, Espedito De Pascale, juo Alfonso Vignoli. Nonlinear Spectral Theory. Berlin ; New York: Walter de Gruyter, 2004.
MLA-čujuhus (9. p.)Appell, Jürgen, et al. Nonlinear Spectral Theory. Walter de Gruyter, 2004.
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