Issue No. 03 - May/June (1973 vol. 6)
The PMS notation was developed to describe the physical structure of computer systems in terms of a small number of elementary components for textbook (Bell and Newell, 1971).
D. Siewiorek, M. Barbacci, C.G. Bell, "PMS: A Notaton to Describe Comuter Sructures", Computer, vol. 6, no. , pp. 19-21, May/June 1973, doi:10.1109/C-M.1973.217034