SULEIMAN, Saleh Duban; ZANZAL, Hassan Thamer. The effect cost of production and marketing cost for improvement the marketing efficiency/analysis student. Tikrit Journal of Administrative and Economic Sciences, [S. l.], v. 17, n. 53, 2, p. 399–408, 2021. DOI: 10.25130/tjaes.17.53.2.24. Disponível em: https://www.tjaes.org/index.php/tjaes/article/view/1738. Acesso em: 29 jul. 2026.