Geometri spektralReferensi
- Berger, Marcel; Gauduchon, Paul; Mazet, Edmond (1971), Le spectre d'une variété riemannienne, Lecture Notes in Mathematics (dalam bahasa Prancis), vol. 194, Berlin-New York: Springer-Verlag.
- Sunada, Toshikazu (1985), "Riemannian coverings and isospectral manifolds", Ann. of Math., 121 (1): 169–186, doi:10.2307/1971195, JSTOR 1971195.