Παραπομπή σε μορφή APA (7η εκδ.)

Helgason, S. (1984). Groups and geometric analysis: Integral geometry, invariant differential operators, and spherical functions. Academic Press.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Helgason, Sigurdur. Groups and Geometric Analysis: Integral Geometry, Invariant Differential Operators, and Spherical Functions. Orlando: Academic Press, 1984.

Παραπομπή σε μορφή MLA (8th εκδ.)

Helgason, Sigurdur. Groups and Geometric Analysis: Integral Geometry, Invariant Differential Operators, and Spherical Functions. Academic Press, 1984.