Kao Pan is described in [Hodgson, 1967], pp 536 - 537. Pink-orange tinge in flesh, bitter flavor; NOT Kao Pan. (EM Nauer, 12/21/1987)
Does not fit the description of Kao Panne [sic], has bitter flavor. (EM Nauer, 10/1988)
PI 109683 was mistakenly assigned the redundant PI 539377 in 1990; observations were made while it was assigned PI 539377, and distributions prior to today. Additional information on Kao Pan is available in Reinking and Groff (1921), Groff (1927), and Martin and Cooper (1977). (RR Krueger, 2014-06-03)
Additional information on PI 109685 from the UC Riverside Citrus Variety Collection is available here.