1. Department of Mathematics and Statistics, The University of Melbourne, VIC 3010 Australia, N.Beaton@pgrad.unimelb.edu.au
2. Algorithms Project, INRIA-Rocquencourt, 78513 Le Chesnay, France, Philippe.Flajolet@inria.fr
3. School of Mathematical Sciences, Monash University, VIC 3800 Australia, tim.garoni@dmonash.edu
4. Department of Mathematics and Statistics, The University of Melbourne, VIC 3010 Australia, T.Guttmann@ms.unimelb.edu.au