On group-divisible designs with block size four and group-type 6um1 Original Research Article

We determine, up to 13 possible exceptions, the spectrum for {4}-GDDs with group-type 6um1. As an application, we construct a new class of Kirkman frames and use these to complete the spectrum for incomplete nearly Kirkman triple systems INKTS(v,w) where v−w≡0 mod 12.