William Lowell Putnam Mathematical Competition Problems and Solutions: 1938-1964

METHODS OF HILBERT SPACES by KRZYSZTOF MAURIN (2nd Rev. Ed.)

Principles of Mathematics by Cletus O. Oakley and Carl B. Allendoerfer

Astronomy and Cosmology, Hoyle, Sir Fred vintage book 1975

Space Mathematics: Math problems based on space science... - Kastner, Kastner

Complex Geometry from Riemann to Kähler- Einstein & Calabi - Yau 2018 Rare!

The Variational Principles of - Paperback, by Cornelius Lanczos - Very Good

The Variational Principles of Mechanics - Paperback, by Cornelius Lanczos - Good