a1 Department of Pure Mathematics, University College, Cardiff.
In an article  in a volume of papers dedicated to the memory of Edmund Landau, Heilbronn investigates the following problem on continued fractions, posed by Dr. J. Gillis:
Let a and N be natural numbers such that 1 ≤ a < N and (a, N) = 1. Then there exist unique natural numbers ci such that
(Received December 20 1974)