Combinatorics: Room Squares, Sum-Free Sets, Hadamard Matrices (with W. D. Wallis and Jennifer Seberry Wallis, Springer, Lecture Notes in Mathematics 292, 1972)[5] Combinatorial Theory: An Introduction (with W. D. Wallis, Charles Babbage Research Centre, 1977)[12] Combinatorics: A First Course (with W. D. Wallis, Charles Babbage Research Centre, 1982)[13] Combinatorics of Experimental Design (with Deborah J. Street, Oxford University Press, 1987)[11] Discrete Mathematics: Logic and Structures (with Elizabeth J. Billington, Melbourne: Longman Cheshire, 1990; 2nd ed., 1993)[14]