Anderson, Robert H., Norman Shapiro, Tora K. Bikson and Phyllis Kantar. "The Design of the MH Mail System". Santa Monica, CA: RAND Corporation, 1989. https://www.rand.org/pubs/notes/N3017. Also available in print form.
Shapiro, Norman and Robert H. Anderson. "Toward an Ethics and Etiquette for Electronic Mail". Santa Monica, CA: RAND Corporation, 1985. https://www.rand.org/pubs/reports/R3283. Also available in print form.