There are literally hundreds of papers about BBNs - most are highly technical. An easily accessible set of papers can be found in the Resources section of the Agena website.
For an extensive set of BBN references visit the website: "A Roadmap to Research on Bayesian Networks and other Decomposable Probabilistic Models" hosted by Lonnie Chrisman, School of Computer Science, Pittsburgh
Also worth looking at are:
Special Issue on Bayesian Networks: Communications of the ACM., March, 1995, vol 38, no. 3.
Special Issue on Data Mining: Communications of the ACM., November, 1996, vol 39, no. 11.
D. Heckerman. A tutorial on learning Bayesian networks. Technical Report MSR-TR-95-06, Microsoft Research, March, 1995.