Modified group divisible designs with block size four
The authors establish the existence of modified group-divisible designs with block size four except when \((m,n)= (6,4)\) [non-existent] and when \((m,n)= (6,16)\) or \((6,22)\) or \((10,15)\) or \((10,18)\) [4 undecided cases].
scientific article; zbMATH DE number 1462329