Much of his work has been done in pioneering techniques in graph theory. He has discovered many results involving
Latin squares, including, In 1998, he was awarded the
Euler Medal for "a distinguished career in the work he has produced, the people he has trained, and his leadership in the development of combinatorics in Britain." Among the specific things cited for are the creation of two new techniques for solving long standing problems. Through the use of
edge colorings in the context of embedding graphs, he was able to settle the Evan's conjecture and the Lindner conjecture. Through the use of
graph amalgamations he was able to show many results, including a method for enumerating
Hamiltonian decompositions as well as a
conjecture about embedding partial triple systems. == References ==