Dianne Barwick identified Jacky Jacky was a Wurundjeri ngurungaeta who died around 1851 and was the oldest brother of Billibellary. Jacky Jacky was also know as Borrunupton.
Diane E. Barwick (1984) 'Mapping the Past: An Atlas of Victorian Clans, 1835-1904, Part I', Aboriginal History, vol. 8, no. 2, pp. 100-131, p. 122.