Occurrence, c., Soil Science Society of America, D. S., Nettleton, W. O., Allen, B. L., Hallmark, C. T., Luxmore, R. J., & Ernst, S. (1991). Proceedings of the symposium (1 edición.). Wisconsin, Estados Unidos: Soil Science Society of America, Inc..

Occurrence, characteristics, Division S-5 Soil Science Society of America, W. O. Nettleton, B. L. Allen, C. T. Hallmark, R. J. Luxmore, and Susan Ernst. Proceedings of the Symposium. 1 edición. Wisconsin, Estados Unidos: Soil Science Society of America, Inc., 1991.

Occurrence, characteristics, et al. Proceedings of the Symposium. 1 edición. Wisconsin, Estados Unidos: Soil Science Society of America, Inc., 1991.