Das, Susma, et al. “Efficient Synthesis of Diversely Substituted pyrazolo[1,5-a]pyrimidine Derivatives Promoted by Ultrasound Irradiation in Water and Their Antibacterial Activities”. European Journal of Chemistry, vol. 11, no. 4, Dec. 2020, pp. 304-13, doi:10.5155/eurjchem.11.4.304-313.2033.