Bofill, P. & Torras, C., "MBMUDs: a combinatorial extension of BIBDs showing good optimality behaviour", Journal of Statistical Planning and Inference 124 (2004) 185-204. www.ElsevierMathematics.com, powered by Science Direct.
Code for the generation of MBMUDs (last revision 29 July 2004): README, C source code, Windows binary.