G. H. Hardy, J. E. Littlewood, Marcel Riesz, Gösta Mittag-Leffler - Acta Mathematica - Collection of Original Fascicules (Vols. 20, 37, 81, 84; 1896–1951) - 1895

Exceptional set of 5 originally softcover volumes/fascicles from the prestigious journal Acta Mathematica, covering a key period in the history of modern mathematics and theoretical physics (1895–1951).
This set includes foundational texts of absolute historical importance:
Volume 19 (1895): Pierre Cousin ("On the functions of n complex variables", pp. 1-61 - Birth certificate of Cousin's problems) & Eugen Netto.
Volume 20 - Fascicles 1 & 2 complete (1896): Henri Poincaré ("The Neumann method and the Dirichlet problem"), Vito Volterra ("Sulla inversione degli integrali definiti"), & Jacques Hadamard. Masterpiece.

Volume 37 - Fascicles 2 & 3 complete (1914): G. H. Hardy & J. E. Littlewood ("Some problems of Diophantine approximation" - Basis of the circle method) & Sven Wigert.

Volume 81 (1949): Marcel Riesz (monumental monograph on the Riemann–Liouville integral and the Cauchy problem, 222 pages).
Volume 84 - Fascicle 3-4 (1951): Tibor Szele.
Origin: former university library. All volumes bear official stamps indicating they were formally declassified.
Condition and restoration: Copies for study of the period, sold as is. Volume 20/1 is in good condition, Volume 20/2 has a torn cover. Volume 37 (1914) has fractured spines and the original covers torn. The other volumes are in fair used condition. Interiors generally clean, texts fully complete and legible. Note: restoration (rebinding or spine and cover consolidation) is necessary for the most affected volumes (1896 and 1914). Please carefully examine the detailed photos before bidding.