Calculus in 1969

Linear Partial Differential Operators by Hörmander, Lars

Real and Abstract Analysis by Hewitt, Edwin, Stromberg, Karl

Integral Operators in the Theory of Linear Partial Differential Equations by Bergman, Stefan

Generalized Feynman Amplitudes by Speer, Eugene R.

Theorie Der Funktionen Einer Reellen Veränderlichen by Natanson, I. P.