Queen, Spencer, Zentmayer and others:Blanchard & Lea, Philadelphia, Medical, Surgical and Scientific Publications, 1859; T.H.McAllister, Illustrated Price List of Microscopes....etc., 1877; James W. Queen & Co., various catalogues, 1869, 1886, 1893, 1897; Joseph Zentmayer, catalogues, 13th edition, n.d., and 15th edition, 1895; Spencer Lens Company, general catalogue 1924 and catalogue of The More Popular Microscopes ....... Accessories, 1930; Eimer & Amend, New York, catalogue of Microscopes etc., 1923; American Optical Company, Three American Microscope Builders, 1945 (12)