Journal Article
On the existence of a PBD(30,{4,5,7,8*})
Grüttmüller, M., Streso, K.
Journal of Combinatorial Designs, 12:4, 271–278 (2004)
Abstract
In the present paper, we will prove by an exhaustive search method that a pairwise balanced design on 30 points with blocks of size 4,5,7 and exactly one block of size 8 does not exist.