Limiting to (mostly) free web-accessible sources, some additonal starting points (click to show full answer):
Here's an article from Women's eNews about one of the cases you refer to, which will give more background, and links to related articles from their site.
The California Coalition for Women Prisoners has an article from the same time (2003) about a protest against Davis' policy. Given you area of research, this seems like a good group to reach out to; their contact info is on the site.
There's also an article on AlterNet.
In 2001, an article in the Christian Science Monitor noted that a California court had ruled Davis' policy of denying parole unconstitutional (this is the case referred to in the New York Times article cited above), and in 2002 the ACLUs of California (North and South) filed a brief to that effect (see the press release).