Optimum constant-thrust transfers?

There has been a lot of work done on Hohman and Bielliptic transfers,
but has there been anything on constant-thrust transfers? Of course, the
"optimum" in this case won't be lowest deltaV, but shortest time for a
given acceleration?

Does anyone have any pointers to online papers?

-bertil-
--
"It can be shown that for any nutty theory, beyond-the-fringe political view or
strange religion there exists a proponent on the Net. The proof is left as an
exercise for your kill-file."