1. Graceful 2-regular graphs and Skolem sequences;Abrham;Discrete Math.,1991
2. Extension of graceful valuations of 2-regular bipartite graphs;Abrham;Cong. Numer.,1991
3. Existence theorems for certain types of graceful valuations of snakes;Abrham,1993
4. On the missing value in a graceful numbering of a 2-regular graph;Abrham,1988
5. Experimental lower bounds for the number of graceful valuations of snakes;Abrham,1990