"Summer Seminar on Applied Mathematics (4th : 1965 : Cornell University)" . . . "Astrophysique." . . "Matematica Aplicada." . . "Astrofysica." . . . . . . . . . . . . "Relativity theory and astrophysics" . "Relativity theory and astrophysics"@en . . . . . . . . . . . . "Relativiteitstheorie." . . "Summer Seminar on Applied Mathematics,4Th,Cornell University,1965." . . . . "Relativité (Physique)" . .