Prokop, V., S. Amponsah Odei, és J. Stejskal. „Does Co-Operation Affect Positively Innovative Performance? Case Study of Estonia and Romania”. Marketing &Amp; Menedzsment, köt. 51, sz. 4, 2017. december, o. 49-58, https://journals.lib.pte.hu/index.php/mm/article/view/867.