My usual reading was from Danforth. For specific OB issues I've always gone to Williams (now switching to Gabbe for fellowship since that is what they like), GYN to TeLinde, Onco to DeSaia, and REI to Speroff.
For CREOGS though, stick to Precis and Prologs as they are the quickest reads specially with respect to REI and Onco.
Good luck!