1. A new and uniform method of recording the hearing power in otological practice Author(s): Prout, J. S. (Jonathan Slater), author Publication: [Boston?] : [publisher not identified], [1872?] Subject(s): Hearing Tests -- standardsReference Standards
2. The dioptric system, and its relation to the old system of numbering lenses Author(s): Ferguson, R. Maupin, author Publication: [Louisville?] : [publisher not identified], [1885?] Subject(s): EyeglassesPrescriptionsReference Standards