In Malaysia's perspective, Point 43/Point C would be the common tripoint for Malaysia, Thailand and Vietnam, and thus the westernmost terminus of the Malaysia-Vietnam common border. Thailand and Vietnam do not recognise this position as they does not recognise Malaysia's continental shelf boundary asserted in the 1979 map. Both countries signed a memorandum of understanding on 5 June 1992 to allow joint exploitation of natural resources in the area of overlapping claims, which the agreement called the Defined Area. The area is also known as Block PM3 Commercial Arrangement Area or CAA (see below). The western portion of the overlapping claim area is also claimed by Thailand and that area is currently included in the Malaysia–Thailand joint development area. The Defined Area established under the 1992 MOU does not include this area. In 1999, all three countries agreed in principle to jointly develop this area using joint development principles. Malaysia and Vietnam both have overlapping claims in the South China Sea involving the continental shelf as well as the islands of the Spratly group. Both Malaysia and Vietnam are two of several countries asserting claims over the islands and waters of the area. Because of the uncertainty, no maritime border agreement exists for the area. Malaysia claims a portion of the South China Sea together with 11 islands and other marine features in the Spratly group on the basis that they are within its continental shelf. Brunei, China, the Philippines and Vietnam also have overlapping claims over the entire or a portion of the area claimed by Malaysia. Malaysia currently occupies one island - Swallow Reef or Pulau Layang-Layang - five reefs and one shoal. It also claims two marine features currently occupied by Vietnam, namely Amboyna Cay and Barque Canada Reef. Amboyna Cay is also claimed by the Philippines. Malaysia claims Commodore Reef which is occupied by the Philippines and Royal Charlotte Reef which is currently not occupied. All the features claimed by Malaysia are also claimed by Vietnam and China (as well as Taiwan). Five features currently occupied by Malaysia are claimed by the Philippines and one is claimed by Brunei. Vietnam claims the entire Spratly Islands group based on historic grounds, and as such, claims all 11 islands and other marine features occupied as well as claimed by Malaysia. It currently has possession of six islands, 17 reefs and three banks and of these, one island and a reef - Amboyna Cay and Barque Canada Reef/Lizzie Weber Reef - are claimed by Malaysia. Other features claimed by Vietnam are currently occupied by China, the Philippines and Taiwan.