1. Extending t-designs;Alltop;J. Combinatorial Theory Ser A,1975
2. A new balanced incomplete block design;Bhattacharya;Sci. Cult.,1944
3. Combinatorial Theory;Hall,1967
4. Non-embeddable quasi-residual designs;van Lint;Indag. Math.,1978
5. J. H. van Lint, private communication.