"A DDCMP based Communications Protocol for the Vending Industry Data Transfer Standard," International Edition, Version 2, Feb. 1, 1992, pp. 5.i through 5.38 from a manual entitled The Vending Industry Data Standard produced for distribution to the members of the National Automatic Merchandising Association. |
"Low Speed Optical Comms Link for the Vending Industry Data Transfer Standard," American Edition, Appendix A Draft 1, Jun. 12, 1990. pp. 5.Ai through 5.A8 from a manual entitled The Vending Industry Data Standard produced for distribution to the members of the National Automatic Merchandising Association. |
Wick, J. "A Question and Answer Guide to Electronic Audit Systems," 1992. The Greenwick Company Inc. of Parkesburg, Pa. 20 pages plus an Audit Product Comparison Checklist (2 pages), no month. |
DDCMP, Version 4.0, Mar. 1, 1978. |
W. Stallings, Data Computer Communications, pp. 105-110 (MacMillan Publishing Co. 1985) Month Unknown. |