非公式帝国
John Gallagher and Ronald Robinson, (1953) "The Imperialism of Free Trade", The Economic History Review, Second series, Vol. VI, no. 1. An online version of this seminal article is available at: http://www.mtholyoke.edu/acad/intrel/ipe/gallagher.htm
A.. H. Imlah,(1952) 'British Balance of Payments and Exports of Capital, 1816-1913', Econ. Hist. Rev. 2nd ser. V, pp. 237, 239; Hancock, op. cit. p. 27.
Barton, G.A. and B.M. Bennett, (2010) Forestry as Foreign Policy: Anglo-Siamese Relations and the Origins of Britain's Informal Empire in the Teak Forests of Northern Siam, 1883–1925 34 (1): 65-86