Unix Relational Database Management: Application Development in the Unix Environment, Rod Manis, Evan Schaffer and Robert Jorgensen, Prentice Hall, 1988. Complete documentation of the /rdb system plus excellent advice on Unix programming in general.
The /rdb web site, http://www.rdb.com/, provides complete product description, pricing and return policies, man pages, on-line demos and demo sources.
The Melody Shop, http://www.rdb.com/Html/melody.html, is a searchable /rdb database containing entries for over 90,000 musical recordings.
The Global Network Academy (GNA), http://www.gnacademy.org/, is a searchable /rdb database containing entries for over 10,000 distance learning courses and degree programs.