Our printout on reading the staves covers the bass clef on page 4.
Finally, I'd recommend that you use a computer program or smartphone app for extra practice. Here are a few that I recommend:
Mac / PCRobert Whelan has a nice bass clef quizzer which will work through any java-enabled browser. Again, I recommend you go into the settings and turn off most of the notes, to start with a small set and build from there.
iPhone / iPadTenuto ($4) and Music Tutor (free).
AndroidSight Read Music and Note Trainer. The latter requires familiarity with the piano keyboard.