Chicago Journal of Theoretical Computer Science (special
issue for CATS 2009)
Volume 2010 Article 8.
This subsumes a paper titled Non-commutative computation, depth reduction, and skew circuits by Meena Mahajan and V Vinay, that appeared in the Proceedings of the 14th International Foundations of Software Technology and Theoretical Computer Science FST&TCS Conference Dec 1994 (Madras), in the Springer-Verlag Lecture Notes in Computer Science series Vol 880, pp. 48--59.