@inproceedings{STOC-1980-CarlsonS,
	author        = "David A. Carlson and John E. Savage",
	booktitle     = "{Proceedings of the 12th Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/800141.804681",
	pages         = "326--332",
	publisher     = "{ACM}",
	title         = "{Graph Pebbling with Many Free Pebbles can be Difficult}",
	year          = 1980,
}