For this reason, most MPAs have been located in territorial waters, where enforcement can be ensured. However, MPAs can also be established in a state's exclusive economic zone 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 recommend that a variety of possible management systems be considered when designing a protected area system. They advocate that MPAs be seen as one of many "nodes" in a network of protected areas.[17] The following are the most commonly used individual types of management systems for MPAs;