Sweet’s indexed catalogue of building construction for the year 1906 (1906)
New York : Chicago : Architectural Record · leaf 470
Fig. 4. Double Gear. For moving two doors in opposite directions at the same time … Width of back plate from4 to 6. No head roomrequired. Fig. 5. CLOSED. Screiv Device for moving two doors in opposite directions
Building materials
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![An illustration from Illustrated catalogue of the extraordinary collection of art treasures and antiquities acquired during the past year by Professore Commendatore Elia Volpi ... to be sold at unrestricted public sale at the American Art Galleries [on Monday, Tuesday and Wednesday afternoon, Dec. 17th, 18th and 19th, 1917] (1917)](https://img.insideoutlibrary.com/img/200/ia-illustratedcatal00volp-350-268.webp)
