1
Published: 1928
Superior document: Reprint / Bell Telephone Laboratories B-302
2
Published: 1935
Superior document: Bell telephone system B-902
3
Published: 1937
Superior document: Bell telephone system B-1023
4
Published: 1929
Superior document: Reprint / Bell Telephone Laboratories B-433
5
Published: 1933
Superior document: Bell telephone system B-733
6
7
Published: 1931
Superior document: Bell telephone system B-551