Laxmi Bachanalaya
Legally available public-domain books and openly licensed reading materials.
Ernest Vessiot
H. Laurent
Karl Weierstrass
Hermann Sieveking
George Whitehead Hearn
Henri Poincaré
Various
Leo Koenigsberger
Karl Joseph Bobek
Albert Ribaucour
H. Bryon Heywood and Maurice Fréchet
Charles Briot and M. Bouquet
Vito Volterra
R. Clausius
Robert J. Nemiroff and Jerry T. Bonnell
François de Salvert
Friedrich Schottky
Wolfgang Vogt
Otto Bohler
D. Bierens de Haan
These books are free to read. Each is in the public domain in the United States; check your own country's rules before you copy or share one.