Hyper-G: A Universal Hypermedia System (cf. Kappe, Maurer & Sherbakov 93). For a demo session with a simple client: telnet to finfo.tu-graz.ac.at and login as info. It can be accessed in limited ways by W3 clients (http ??).
JITOL
CSILE: (cf. Scardamalia)

(Appendixes are getting worse, dont they ?)