Keddie, G. (1989) Symbolism and Context: The World History of the Labret and Cultural Diffusion on the Pacific Rim, Pennad diembann, lennet er Circum-Pacific Prehistory Conference: Seattle [www.bcarchives.bc.ca/Content_Files/Files/LABRETW89PAPERSept5-07forWeb.pdf Teuliad pdf da diskargañ]