[49: "Study on Cross-Border Cooperation: Capitalising on existing initiatives for cooperation in cross-border regions", Gesundheit Österreich Forschungs und Planungs GmbH, SOGETI, Maastricht University, 2017][50: See the General Secretariat of the Benelux Union studies, e.g. "Barriers and Opportunities in the Benelux", February 2018.]
[49: Study on Cross-Border Cooperation: Capitalising on existing initiatives for cooperation in cross-border regions (Studija o prekograničnoj suradnji:iskorištavanje postojećih inicijativa za suradnju u prekograničnim regijama), Gesundheit Österreich Forschungs und Planungs GmbH, SOGETI, Maastricht University, 2017.][50: Vidjeti studije Glavnog tajništva unije Beneluksa, npr.