1. Simply sequential and graceful graphs;Bange,1979
2. Graceful graphs, radio antennae and French windmills;Bermond,1979
3. A chronology of the Ringel-Kotzig conjecture and the continuing quest to call all trees graceful;Bloom,1977
4. How to number a graph;Golomb,1972
5. On additive bases and harmonious graphs;Graham;SIAM J. Algebraic Discrete Methods,1980