^There is variance on the date of Grimketels death and Hecas accession between the various versions of the Anglo-Saxon chronicle. The Anglo-Saxon Chronicle manuscript (MS) C suggests that Grimketel died in 1047. According to the Anglo-Saxon Chronicle MS E, MS F and MS D he could also have died in 1045, 1046 or 1047
^Anglo-Saxon Chronicle versions E and F give his date of death as 1058, the other manuscripts cite 1057.
Barlow, Frank (1979). The English Church 1000–1066: A History of the Later Anglo-Saxon Church (Second ed.). New York: Longman. ISBN0-582-49049-9.
Fryde, E. B.; Greenway, D. E.; Porter, S.; Roy, I. (1996). Handbook of British Chronology (Third revised ed.). Cambridge, UK: Cambridge University Press. ISBN0-521-56350-X.
Swanton, Michael James, ed. (1998). The Anglo Saxon chronicle. New York: Routledge. ISBN978-0-415-92129-9.