C-Lock (Patent Pending): A System for Estimating and Certifying Carbon Emission Reduction Credits for the Sequestration of Soil Carbon on Agricultural Land - Zimmerman, Patrick R.; Price, Maribeth; Peng, Changhui; Capehart, William J.; Updegraff, Karen; Kozak, Patrick; Vierling, Lee; Baker, Elaine; Kopp, Fred; Duke, Genet; Das, Chandan (Mitigation and Adaptation Strategies for Global Change, 2005)