In 1968, H. Quitta, J. Herrmann, G. Kohl and P. H. Thong initiated coo
peration between the Archaeological Institute in Hanoi and the Radioca
rbon Dating Laboratory in Berlin. Since 1969, the Berlin C-14 laborato
ry has measured 215 C-14 dates from 65 archaeological sites in Vietnam
. As a result, important problems in Vietnamese archaeology have been
recognized and partially solved with the aid of a secure chronological
framework.