@article{PT78, AUTHOR = {Paul, W.J. and Tarjan, R.E.}, TITLE = {Time-Space Trade-Offs in a Pebble Game}, VOLUME = {10}, YEAR = {1978}, PAGES = {111--115}, SERIES = {Acta Informatica 1978}, EE = {http://www.springerlink.com/content/rq90v3u24j842105/}, }