Most MPAs have been located in territorial waters, where the appropriate government can enforce them. However, MPAs have been established in exclusive economic zones and in international waters. For example, Italy, France and Monaco in 1999 jointly established a cetacean sanctuary in the Ligurian Sea named the Pelagos Sanctuary for Mediterranean Marine Mammals. This sanctuary includes both national and international waters. Both the CBD and IUCN recommended a variety of management systems for use in a protected area system. They advocated that MPAs be seen as one of many "nodes" in a network of protected areas. The following are the most common management systems: