"Funktion <Mathematik>" . . "Funciones de variable real." . . "Kalkulus." . . "Fonctions d'une variable réelle." . . "Valós függvénytan." . . "Matemática." . . "Analysis." . . "Funktionentheorie." . . . . . . . . "Introduction to the theory of functions of a real variable" . "Introduction to the theory of functions of a real variable"@en . . . . . "An Introduction to the theory of functions of a real variable" . . . . . . "An introduction to the theory of functions of a real variable*" . "An introdution to the theory of functions of a real variable" . . . . . . . . . "An introduction to the theory of functions of a real variable" . "An introduction to the theory of functions of a real variable"@en . . . . . . . . . . . . .