Gardner, Anne-Christine. 2011. "Word formation in Early Middle English: Abstract nouns in the Linguistic Atlas of Early Middle English." Studies in Variation, Contacts and Change in English 6: Methodological and Historical Dimensions of Corpus Linguistics.
Garner, Bryan A. 2003. Garner’s Modern American Usage. 2nd edition. Oxford: Oxford University Press.
Garrett, A. 1998. "On the Origin of Auxiliary Do." ELL 2: 283-330.