1 23 VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations Official journal of the International Society for Third-Sector Research ISSN 0957-8765 Voluntas DOI 10.1007/s11266-020-00213-w Mapping the Field of Donation-Based Crowdfunding for Charitable Causes: Systematic Review and Conceptual Framework Noelia Salido-Andres, Marta Rey- Garcia, Luis Ignacio Alvarez-Gonzalez & Rodolfo Vazquez-Casielles