The role of differential analysis by multi- levels contribution margin in accordance with German Cost Accounting (GPK) in optimizing non-routine decision-making Field Study: Evening Studies at the Institute of Administration / Rusafa. Entrepreneurship Journal for Finance and Business, [S. l.], v. 5, n. 1, p. 06–21, 2024. DOI: 10.56967/ejfb2024363. Disponível em: https://ejfb.journalpath.com/ejfb/article/view/200. Acesso em: 19 jul. 2026.