TitleWestern Carolines:Helen ReefContributorAllied Geographical SectionDescriptionContains the inset map Helen Channel Reproduced from Advance copy H.O. Chart no. 12026. From survey by the Imp. Japanese Navy in 1918; Published 14 May 1927; Corrected to 1942 Scale: 02:12.6LanguageEnglish
Allied Geographical Section South West Pacific Area Terrain Studies (1944). Monash Uni, accessed 30/04/2026, https://collections.monash.edu/nodes/view/77631
