Arifin, Y., S. D. Permai, H. Pudjihastuti, K. Dwiputra, F. R. Faisal, and M. Marcellino. “UNTUKMU.COM : THE CROWDSOURCING APPLICATION TO LEVERAGING THE USED OF SECONDHAND GOODS”. Social Economics and Ecology International Journal (SEEIJ), vol. 2, no. 2, Oct. 2021, doi:10.21512/seeij.v2i2.5635.