Mari didn't mention it, but her diss. on aspect is worth perusing:
"A Semantic and Pragmatic Model of Lexical and Grammatical Aspect"
Ph.D., Northwestern Univ., 1994.
In regard to the terminology 'default', or better, 'unmarked', here is the
def. of 'Markedness' from _International Encyclopedia of Linguistics_, ed.
William Bright, 4 vols. (New York: Oxford Univ. Press, 1992).
Markedness is "the concept by which a particular quality is
regarded as neutral or expected, i.e., 'unmarked', whereas an alternative,
more unusual quality is considered 'marked' (2:390).
The term originated in Chomsky's generative grammar as related to phonology
and has only received significant attention in syntax in the 1980s.
Rodney J. Decker, Asst. Prof./NT Baptist Bible Seminary
email@example.com Clarks Summit, PA