Mandate Palestine
British / U.K. Foreign Office on Palestine publications in Harvard's HOLLIS Catalog
British / U.K. Parliamentary Papers search for "Palestine" 1918-1950. (Link for Harvard subscription only. This link populates the search form in the database. You need to click on "search" to make it run. Then you can use "search within results" to narrow it down.)
League of Nations publications on Palestine in Harvard's HOLLIS Catalog
Mandate for Palestine, text of the League of Nations Document