Fhrizz De Jesus, et al. “PPRR MODEL ANALYSIS OF TRAVEL AGENCIES BUSINESS OPERATIONS AMIDST THE COVID-19 PANDEMIC: BASIS FOR CONTINUITY PLAN”. Asian Journal of Multidisciplinary Research & Review, vol. 3, no. 1, Jan. 2022, pp. 79-106, https://ajmrr.org/journal/article/view/22.