Two Constructions of (v, (v-1)/2, (v-3)/2) difference families

In this article, two constructions of (nu, (nu - 1)/2, (nu - 3)/2) difference families are presented. The first construction produces both cyclic and noncyclic difference families, while the second one gives only cyclic difference families. The parameters of the second construction are new. The difference families presented in this article can be used to construct Hadamard matrices. (C) 2007 Wiley Periodicals, Inc