Thanks, Josette, for your reply. The thing about the IMDB is that it is "fan"-supported, i.e., movie afficionados make all the contributions to the database. If you look up LI'L ABNER (1959), you'll see that Valerie Harper (RHODA) is listed as an uncredited dancer: I supplied that info after noticing Harper in the chorus of the film. I also supplied info on Beth Howland (ALICE) and Donna Douglas (BEVERLY HILLBILLIES), both of whom also appear in ABNER. I'm going to be adding some more credit information to A DARKNESS AT BLAISEDON soon--I just haven't taken the time. Also, beware: some of the information on the IMDB is incorrect. Again, it's all because people like you and me supply the material.
But thanks for your suggestion.
Brian