British Electoral Facts 1832-1999, compiled and edited by Colin Rallings and Michael Thrasher (Ashgate Publishing Ltd 2000). (For dates of elections before 1832, see the footnote to Table 5.02).
Namier, L. B., & Brooke, J. (1964). The House of Commons, 1754–1790. New York, Published for the History of Parliament Trust by Oxford University Press.