Chowdhury, S.R. and Saha, D. trans. 2026. Understanding Innovation in Small Firms: A Systematic Literature Review of Heterogeneity in Definitions, Drivers, and Measurement. West Science Journal Economic and Entrepreneurship. 4, 03 (Aug. 2026), 453–469. DOI:https://doi.org/10.58812/wsjee.v4i03.2853.