2 dissertations on online learning:

1. Santo, S.A.: "Virtual learning, personality, and learning styles". Dissertation Abstracts International Section A, Humanities & Social Sciences, 62, pp. 137 (2001) (slides: http://sloanconsortium.org/conference/proceedings/1999/pdf/99_santo.pdf )
2. Zobdeh-Asadi, S.: "Differences in personality factors and learners' preference for traditional versus online education". Dissertation Abstract International Section A: Humanities & Social Sciences, 65(2-A), pp. 436 (2004)

(I requested these a month ago on /r/scholar but they apparently couldn't help.)