The Bell System Technical Journal vol XLIV, number 4, April 1965.
American Telephone and Telegraph Co., NY 1965, pp 547-729 inclusive, diagrams, some photos, references.
American Telephone and Telegraph Co., NY 1965, pp 547-729 inclusive, diagrams, some photos, references.
AT&T, March 1965, pp 373-pp 546 inclusive, references, diagrams.
AT&T 1965, pp 207-372 inclusive, diagrams and photographs, references.
Bell Tel. Labs, NY 1947, 1956, 1963, 43 pages, diagrams, tables, references.
Bell System, November 1970, pp 1995-2415 inclusive, diagrams, references, some photographs.
Bell Telephone Laboratories, November 1926, Reprint B-212, reprint of a paper presented at annual meeting of telegraph and telephone section of the Ameircan Railway Association September1926; and published in their Proceedings; 16 pages, some illustr.
AT&T, issued October 1953, orig. published in The Bell System Technical Journal, vol 32, March 1953; 24 pages plus rear foldout chart.