AtwoodE. Bagby. 1953. Survey A. of Verb Forms in the Eastern United States.Ann Arbor: University of Michigan Press.
2.
Baugh, AlbertC.1963. History A. of the English Language.2nd ed. New York: Appleton-Century-Crofts.
3.
BolingerDwight. 1971a. The Nominal in the Progressive. Linguistic Inquiry2:246–50.
4.
BolingerDwight. 1971b. FurtherA.Note on the Nominal in the Progressive. Linguistic Inquiry2:284–87.
5.
Buffington, AlbertF., and PrestonA. Barba. 1965. Pennsylvania A. German Grammar.Allentown, PA: Schlechter.
6.
FeaginCrawford. 1979. Variation and Change in Alabama English: Sociolinguistic A. Study of the White Community.Washington: Georgetown University Press.
7.
DorianNancy C.1981. Language Death: The Life Cycle of a Scottish Gaelic Dialect.Philadelphia: University of Pennsylvania Press.
8.
FreyJ. William. 1981. Simple A. Grammar of Pennsylvania German. Reissued, new preface by BeamC. R.Lancaster, PA: Brookshire.
9.
Haag, EarlC.1982. Pennsylvania A. German Reader and Grammar.University Park, PA: Pennsylvania State University Press.
10.
HuffinesMarion Lois. 1986. The Function of Aspect in Pennsylvania German and the Impact of English. Yearbook for German-American Studies21:137–54.
11.
HuffinesMarion Lois. 1989. Case Usage among the Pennsylvania German Sectarians and Nonsectarians. In Nancy Dorian C., ed., Investigating Obsolescence: Studies in Language Contraction and Death (Cambridge: Cambridge University Press), 211–26.
12.
Sag, IvanA.1973. On the State of Progress on Progressives and Statives. In C.-J. Bailey and Roger Shuy W., eds., New Ways of Analyzing Variation in English (Washington: Georgetown University Press), 83–95.
13.
Reed, CarrollE.1947. The Question of Aspect in Pennsylvania German. Germanic Review22:5–12.
14.
TwainMark. 1982. Mississippi Writings.CardwellGuy, ed. New York: Library of America.
15.
Van der GaafW.1930. Some Notes on the History of the Progressive Form. Neophilologus15:201–15.
16.
VisserF.Th. 1963-69. An Historical Syntax of the English Language. 4 vols. Leiden: Brill.
17.
WolframWalt. 1980. a-prefixing in Appalachian English. In William Labov, ed., Locating Language in Time and Space (New York: Academic Press), 107–42.
18.
WolframWalt. and DonnaChristian. 1976. Appalachian Speech.Arlington: Center for Applied Linguistics.
