It should be noted that this density is reflected in the later figures presented for the Bac Bo
region in the well-known work of Hans Bielenstein (1947) on the Han census of 2 CE, a work which does not appear in Nam Kim's bibliography but one whose findings correlate well with his own.
The incident, in fact, can be added to a consistent pattern of Chinese expansionism in the Eastern Sea: conquest of the Paracel Islands in 1974; occupation of the Spratly archipelagoes in 1979; and annexation of 12,000 square meters of territorial waters in the Vinh Bac Bo conceded by Hanoi under the 2000 Vinh Bac Bo Pact.
The 2000 Vinh Bac Bo Pact includes only a vaguely worded clause stipulating that "when gas is confirmed, the two sides will explore it together." Nguyen Dinh Sai, an engineer who has done extensive research on the Vinh Bac Bo, has written about a secret agreement between Vietnam and China that spells out in detail how the proceeds from gas production would be distributed between the two parties.