The RLE PTP series spans primarily from 1983 – 1996, with three reports that date from the 50’s (according to Barton). There are no copyright statements on the documents that I detected from a quick sampling of the reports in Barker and all the reports in Barker at least are in good condition, bound with a clear plastic front cover, and a colored plastic cover on the back.
Between the Barker and Archives collections there are 121 reports available in total, Barker’s collection contains 78 of them. The call number for the series is QC717.6.M3.R42.
There are Barton records for all of them. Typical record:
http://library.mit.edu/item/000913357
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