@inproceedings{STOC-1970-Rounds,
	author        = "William C. Rounds",
	booktitle     = "{Proceedings of the Second Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/800161.805156",
	pages         = "109--116",
	publisher     = "{ACM}",
	title         = "{Tree-Oriented Proofs of Some Theorems on Context-Free and Indexed Languages}",
	year          = 1970,
}