de Jong, A. F. M., Becker, B., and Mook, W. G. (1986). High-precision calibration of the radiocarbon time scale, 3930-3230 cal BC. Radiocarbon 28: 939-941.
de Jong, AFM, Becker, B, Mook, WG, 1989. Corrected calibration of the radiocarbon time scale. Radiocarbon 31:201-210.