Toledo, I., Lloret, L., Martínez-Romero, E. (2003). <i>Sinorhizobium americanus</i> sp. nov., a new sinorhizobium species nodulating native Acacia spp. in Mexico. <i> Syst.Appl.Microbiol. </i><b> 26 </b>: 54-64 .
(2004). Validation of publication of new names and new combinations previously effectively published outside the IJSEM. List No. 100. <i> Int.J.Syst.Evol.Microbiol. </i><b> 54 </b>: 1909-1910 .

De Lajudie, P., Willems, A., Pot, B., Dewettinck, D., Maestrojuan, G., Neyra, M., Collins, M. D., Dreyfus, B., Kersters, K., Gillis, M. (1994). Polyphasic taxonomy of Rhizobia: emendation of the genus <i>Sinorhizobium</i> and description of <i>Sinorhizobium meliloti</i> comb. nov., <i>Sinorhizobium saheli</i> sp. nov., and <i>Sinorhizobium teranga</i> sp. nov. <i> Int.J.Syst.Bacteriol. </i><b> 44 </b>: 715-733 .
Scholla, M. H., Elkan, G. H. (1984). <i>Rhizobium</i> <i>fredii</i> sp. nov. a fast-growing species that effectively nodulates soybeans. <i> Int.J.Syst.Bacteriol. </i><b> 34 </b>: 484-486 .
Chen, W. X., Yan, G. H., Li, J. L. (1988). Numerical taxonomic study of fast-growing soybean rhizobia and a proposal that <i>Rhizobium</i> <i>fredii</i> be assigned to <i>Sinorhizobium</i> gen. nov. <i> Int.J.Syst.Bacteriol. </i><b> 38 </b>: 392-397 .

Dangeard, P. A. (1926). Recherches sur les tubercles radicaux des Légumineuses. <i> Botaniste </i><b> 16 </b>: 1-275 .
De Lajudie, P., Willems, A., Pot, B., Dewettinck, D., Maestrojuan, G., Neyra, M., Collins, M. D., Dreyfus, B., Kersters, K., Gillis, M. (1994). Polyphasic taxonomy of Rhizobia: emendation of the genus <i>Sinorhizobium</i> and description of <i>Sinorhizobium meliloti</i> comb. nov., <i>Sinorhizobium saheli</i> sp. nov., and <i>Sinorhizobium teranga</i> sp. nov. <i> Int.J.Syst.Bacteriol. </i><b> 44 </b>: 715-733 .
Bergey, D. H., Buchanan, R. E., Gibbons, N. E., (1974). Bergey's manual of determinative Bacteriology. 8th. EditionEdited by R. E. Buchanan, The Williams & Wilkins Co..

Euzeby, J. (2011). List of new names and new combinations previously effectively, but not validly, published. <i> Int J Syst Evol Microbiol </i><b> 61 </b> ( Pt 3 ): 475-476 .
Lloret, L., Ormeño-Orrillo, E., Rincón, R., Martínez-Romero, J., Rogel-Hernández, M. A., Martínez-Romero, E. (2007). <i>Ensifer mexicanus</i> sp. nov. a new species nodulating<i> Acacia angustissima</i> (Mill.) Kuntze in Mexico. <i> Syst Appl Microbiol </i><b> 30 </b> ( 4 ): 280-290 .