The Bell System Technical Journal 1957 LOT of 3 individual issues volume XXXVI numbers 2,3,4 March May July 1957.
AT&T BSTJ 3 individual issues 1957, diagrams, references.
AT&T BSTJ 3 individual issues 1957, diagrams, references.
AT&T, BSTJ, pp 1319-1513 inclusive, photographs, diagrams, references.