Johnstone, Peter (2001), "Elements of the history of locale theory", in Aull, C. E.; Lowen, R. (eds.), Handbook of the History of General Topology, vol. 3, Dordrecht: Kluwer Acad. Publ., pp. 835–851, doi:10.1007/978-94-017-0470-0_2, MR1900266.
Johnstone, Peter (2001), "Elements of the history of locale theory", in Aull, C. E.; Lowen, R. (eds.), Handbook of the History of General Topology, vol. 3, Dordrecht: Kluwer Acad. Publ., pp. 835–851, doi:10.1007/978-94-017-0470-0_2, MR1900266.