Listiawati, Karta Negara Salam, Retno Wulansari, and Pramudi Harsono. 2021. “Promotion Costs Analysis To Increased Volume Sales In The Convection Companies ”. International Journal of Science, Technology & Management 2 (5), 1542-51. https://doi.org/10.46729/ijstm.v2i5.300.