Helgason, Sigurdur, 1927- (Nombre personal)

Old catalog hdg.: Helgason, Sigurður, 1927-

Author's Differential geometry and symmetric spaces, 1962.

His Gruppy i geometricheskiĭ analiz, 1987: t.p. (S. Khelgason)

Stærðfræðingurinn Ólafur Dan Daníelsson, 1996: t.p. (Sigurður Helgason)

Dept. of Math., MIT, Cambridge