Regional Workshop on Cooperation Arrangements in the Field of Preparedness and Response to Oil and Hazardous and Noxious Substances (HNS) Spills (MEDEXPOL 2016): Principles and guidelines concerning cooperation and mutual assistance adopted, by the Seventh Meeting of the Contracting Parties to the Barcelona Convention, Cairo, 11 October 1991 (UNEP(OCA)/MED IG.2/4, Annex IV, Appendices I-VI)