V. . Brar, A. Kumar, and A. . Ramgade, “Problems in Evaluating the Effectiveness of Sales Promotion Activities”, Int. J. Multidiscip. Appl. Bus. Edu. Res., vol. 3, no. 7, pp. 1239–1243, Jul. 2022, doi: 10.11594/ijmaber.03.07.02.