Ellefsen, R., Gaydos, L., Swain, P., and Wray, J.R., 1974, New techniques in mapping urban land use and monitoring change for selected U.S. metropolitan area, an experiment employing computer-assisted analysis of ERTS-1 MSS data, in Proceedings of symposium on remote sensing and photo interpretation, volume 1: Canadian Inst. Surv., p. 51-63.