R. Prasad, R. K. Singh, R. Yadava, and S. Chaurasia, “Growth and nodulation of cowpea [Vigna unguiculata (L.) Walp] as influenced by phosphorus levels and bio-inoculants”, VegSci, vol. 40, no. 02, pp. 204–206, Dec. 2013, doi: 10.61180/.