https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/1192/1197 (Publisher version)
BEX363.pdf (Publisher version), 2MB
Trumbore, S. E., Vogel, J. S., & Southon, J. R. (1989). AMS 14C measurements of fractionated soil organic-matter - an approach to deciphering the soil carbon-cycle. Radiocarbon, 31(3), 644-654. doi:10.1017/S0033822200012248.