المؤلفون: Hardman, J. Reid, Heuberger, D.C., Collins, M.E.

المصدر: Soil Horizons ; volume 39, issue 1, page 1 ; ISSN 2163-2812

الاتاحة: http://dx.doi.org/10.2136/sh1998.1.0001
https://dl.sciencesocieties.org/publications/sh/pdfs/39/1/1