It was verified as part of VLISP project. So, I've been keeping papers on PreScheme, Scheme48, and VLISP in case anyone wants to redo them with modern techniques. Another commenter, hga, helped me find a few I didn't have before with the specific algorithms. The basic ones are on the bottom here:
PreScheme itself is possibly worth reviving esp with ref counting or Rust's type of no-GC safety. I know another LISP, Carp, is trying to do something like the latter.