Titchmarsh, E. C. (1962). Eigenfunction expansions: Associated with second-order differential equations (2nd ed.). Clarendon Press.
Παραπομπή σε μορφή Chicago (17η εκδ.)Titchmarsh, E. C. Eigenfunction Expansions: Associated with Second-order Differential Equations. 2nd ed. Oxford: Clarendon Press, 1962.
Παραπομπή σε μορφή MLA (8th εκδ.)Titchmarsh, E. C. Eigenfunction Expansions: Associated with Second-order Differential Equations. 2nd ed. Clarendon Press, 1962.
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