W. GAERTNER & CO., 1908

Astronomical instruments and accessories : Catalog A : 1908 / W. Gaertner & Co., 5345-5349, Lake Ave., Chicago. – [S.l. : S.n.], 1908 (Chicago : M.L. Vittu). – 28 p. : ill. : 23 cm.
Testo in inglese.