EntrepreEntrepreneurship Knowledge, Challenges, and Sustainable Entrepreneurship Framework for Retirees: A Systematic Reviewneurship Knowledge, Challenges, and Sustainable Entrepreneurship Framework for Retirees: A Systematic Review: Introduction, Methodology, Result and Discussion, Discussion, and Conclusion. . IJIBS. 2024;19(2):1-21. doi:10.11113/ijibs.v19.161