Multiple sulfur isotope fractionations in biological systems: a case study with sulfate reducers and sulfur disproportionators.

Johnston, D. T., Farquhar, J., Wing, B. A., Kaufman, A. J., Canfield, D. E., & Habicht, K. S. (2005). Multiple sulfur isotope fractionations in biological systems: a case study with sulfate reducers and sulfur disproportionators. American Journal of Science , 305 (6-8), 645-660.