Most people's problem with muscle-ups (who can do pull-ups and ring dips) isn't strength, it's technique.
False grip, pull up hard, then violently "break the glass pane in front of you with your forehead" to get into the dip position, then simply ring dip up.
A pull-up program I tried for a while (I got bored with it and decided to do harder pull-up variations a la Coach Sommer to get stronger rather than more and more pull-ups) was the
Recon Ron Pull-up Program.