Toward a comprehensive catalog of global historical seismicity - Villasenor, A.; Bergman, Eric; Boyd, T.M.; Engdahl, E.R.; Frazier, D.W.; Harden, M.M.; Orth, J.L.; Parkes, R.L.; Shedlock, K. (Eos, Transactions, American Geophysical Union, 1997)