JOHNSEN, Erik. Sasieni, Yaspan and Friedman: Operations Research, Methods and Problems, 316 s., 1959. John Wiley and Sons. Ledelse og Erhvervsøkonomi, [S. l.], v. 23, 1959. Disponível em: https://tidsskrift.dk/ledelseogerhvervsoekonomi/article/view/33755. Acesso em: 6 dec. 2025.