Back in 2009, I posted a link to an article by Professor Chris Robinette (Widener) on the "Prosser Notebook" - a notebook of one of Prosser's students at the University of Minnesota in 1938. See here and here.
Chris has now published another article on Prosser's letters which is now available here.
It contains material from an unpublished dissertation
on Prosser's father, who played a crucial role in the development of
vocational education, and materials from the Harvard archives.
Thanks to Chris for the link.