Gibbons of Sumatra: here.
White-cheecked gibbons: here.
From Wildlife Extra:
May 2008. A gibbon subspecies from China’s Yunnan province has been declared extinct by a Chinese-Swiss research team. The white-handed, or lar gibbon, Hylobates lar, was last observed in 1988 in the Nangunhe Nature Reserve in south-western Yunnan province, and the loud, melodious calls of this species of ape were last heard in Yunnan in 1992.
Forestry officials in the north-east Indian state of Assam have demanded the creation of a no-pesticide zone around the famous Kaziranga game sanctuary: here.