^The Oxford companion to Irish history (2nd ed.). Oxford University Press. p. 24. ISBN 9780199691869.
^Lennon, Colm (2004). "Creagh (Crevagh), Richard (c.1523–1586?)". Oxford Dictionary of National Biography. Oxford University Press. doi:10.1093/ref:odnb/6658. Retrieved 2013-02-20. (subscription or UK public library membership required)