43 books
Proceedings of the Academy of Natural Sciences of Philadelphia, 1854, 1855, Vol. 7 (Classic Reprint)
Proceedings of the Academy of Natural Sciences of Philadelphia, 1901, Vol. 53 (Classic Reprint)
Proceedings of the Academy of Natural Sciences of Philadelphia, 1850-1851, Vol. 5 (Classic Reprint)
Proceedings of the Academy of Natural Sciences of Philadelphia, 1902, Vol. 54 (Classic Reprint)
Proceedings of the Academy of Natural Sciences of Philadelphia, 1905, Vol. 57 (Classic Reprint)
Proceedings of the Academy of Natural Sciences of Philadelphia, 1852-1853, Vol. 6 (Classic Reprint)
Proceedings of the Academy of Natural Sciences of Philadelphia, 1918, Vol. 70 (Classic Reprint)