"Sweet's" Catalogue of Building Construction for the Year 1911 With an Introduction and Cross-index, Together with a Checking List for Use in the Making of Specifications and Estimates Devised, Volume 2 (Architectural Record Company, 1913), p.442. Available online in Google Books
http://books.google.com/books?id=1dk_AQAAMAAJ&pg=PA442 (accessed 07/06/2015)