For a while, I've been trying to compile the most comprehensive bibliography of academic materials on or relating to asexuality. The first version was a blog post, and this has been incorporated and expanded into the page Existing Research.
There are some new additions people may be interested in.
Most significantly, a new paper on asexuality has been published online before the journal is printed.
Brotto, L. A., Knudson, G., Inskip, J., Rhodes, K., & Erskine, Y. (in press). Asexuality: A mixed methods approach. Archives of Sexual Behavior.
Also, I found that something like the 2-dimensional model of sexual orientation that was proposed by Michael Storms in 1978 was proposed independently the previous year, though it does not mention asexuality.
Shively, Michael G. and De Cecco, John P.(1977)'Components of Sexual Identity',Journal of Homosexuality,3(1) 41-48
Because of this, I have rewritten and renamed the section containing Storms' works to "Modeling sexual orientation to include asexuality."
Also, I found a dissertation attempting to use such a model, making it one of only two studies I know of to use such a model for sexual orientation and gives data on a group identified as "asexuals."
Conner, Karen Lynn (1996). Covariation of sexual orientation and sexual desire. Ph.D. dissertation, University of Florida, United States
I've also added a section on books I expect to have particular relevance to studying asexuality.
Abstracts and/or commentary on each of this is included in the bibliography.