“Influence of Bio-Inoculants (earthworms and Nitrogen-Fixing Bacteria) on Rhizosphere Microflora of Alfalfa”. Bulgarian Journal of Soil Science, Agrochemistry and Ecology, vol. 53, no. 1, Mar. 2019, pp. 27-34, https://agriacad.eu/ojs/index.php/bjssae/article/view/1865.