Russian Deputy Prime Minister Dmitry Chernyshenko signs a visitors' book at the Joint Russian-Vietnamese Tropical Research and Technological Center, as Director General of the center's Russian side Andrey Kuznetsov, Russian Ambassador to Vietnam Gennady Bezdetko, Vietnamese Deputy Defence Minister Hoang Xuan Chien and Director General of the center's Vietnamese side Major General Dang Hong Trien stand nearby in Hanoi, Vietnam.