1. Douglas D. Grant, Stability and operations on graphs, this volume, 116–135.
2. P. Heffernan, Trees, M.Sc. Thesis, University of Canterbury, New Zealand, 1972.
3. D. A. Holton, Stable trees, Proc. First Austral. Conf. on Combinatorial Mathematics, Eds. Jennifer Wallis and W. D. Wallis, (TUNRA, Newcastle, 1972), 15–21.
4. K. L. McAvaney, Semi-stable and stable cacti, submitted.
5. K. L. McAvaney, Douglas D. Grant, D. A. Holton, Stable and semistable unicyclic graphs. Discrete Maths, to appear.