^"Census Figures by Wards - Islands Region". www.nso.gov.pg. 2011 National Population and Housing Census: Ward Population Profile. Port Moresby: National Statistical Office, Papua New Guinea. 2014. Archived from the original on 2019-10-30. Retrieved 2019-10-10.
^"Final Figures". www.nso.gov.pg. 2011 National Population and Housing Census: Ward Population Profile. Port Moresby: National Statistical Office, Papua New Guinea. 2014. Archived from the original on 2015-09-06. Retrieved 2019-10-10.
^Reesink, Ger. 2005. Sulka of East New Britain: A Mixture of Oceanic and Papuan Traits. Oceanic Linguistics 44. 145-193.