Variants of (v, k, λ)-Designs††This research was supported in part by the Army Research Office, Durham under Grant DA-ARO-D-31-124-G1138 and the Office of Naval Research under Contract N00014-67-A-0094-0010.

Summary The present paper surveys the recent literature on new types of combinatorial designs that are closely related to the classical (v, k,λ)-designs.