Von Humbolt- On Language
Representation and Invariance of Scientific Structures
Moritz Pasch - Vorlesungen Über Die Neuere Geometrie
Alan McMichael; Ed Zalta -- An Alternative Theory of Nonexistent Objects
The Calculus of Individuals and Its Uses 1940
Alternative formulations of propositional logic
[Gerhard Rohlfs.] Grammatica Storica Della Lingua Italiana
Ivan Niven - Irrational Numbers
Basic Topology - A. Armstrong