@inproceedings{STOC-1970-AhoU,
	author        = "Alfred V. Aho and Jeffrey D. Ullman",
	booktitle     = "{Proceedings of the Second Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/800161.805159",
	pages         = "136--148",
	publisher     = "{ACM}",
	title         = "{Transformations on Straight Line Programs-Preliminary Version}",
	year          = 1970,
}