[Haskell-beginners] Where is hugs (or other) version of gofer modular-interpreter code?

Page 2 of: http://www.cs.yale.edu/~liang-sheng/popl95.ps.gz says the source code is at: nebula.cs.yale.edu/pub/yale-fp/modular-interpreter However, that's no longer present. Since Hugs is the successor to gofer, I was wondering if anyone could tell me how to get a copy of the corresponding hugs code. TIA. -Larry