Appendix C, The Sources of Copan Valley ObsidianHarvard University445–458
Harbottle, Garman, Neff, Hector, and Bishop, Ronald L. 1994. "Appendix C, The Sources of Copan Valley Obsidian." In The Copan Residential Zone. Willey, G. R., Leventhal, R. M., Demarest, A. A., and Fash, W. L.,Jr., editors. 445–458. Cambridge: Harvard University.