Di Ciocco, C., C. Coviella, E. Penón, M. Díaz-Zorita, and S. López. 2008. “Short Communication. Biological Fixation of Nitrogen and N Balance in Soybean Crops in the Pampas Region”. Spanish Journal of Agricultural Research 6 (1), 114-19. https://doi.org/10.5424/sjar/2008061-5259.