Jazz Blues on p 97. I am assuming the stemless slashes represent strums. Since this is a medium swing groove the slashes just don't seem to have there usual meaning. So, I could also assume the stemless slashes just represent 4/4 timing and that we can fill in any rhythm that goes with that up strum on the & of 4. I am assuming the intro rhythm isn't to be used for the chorus sections. I'am also assuming that chorus 3 requires a different rhythm than chorus 1 and 2. I am also assuming the ties that don't connect notes actually do.
The reason I asked about the slashes is because of the Hal Leonard Blues Guitar book. It also uses slashes like this course, but when it got to a swing blues exercise the slashes seem to just represent the beats and not a strum pattern. Since they played that exercise with a jam track. I wouldn't bet money on what I thought I was hearing, but it sure sounded like a charleston rhythm and not just strums.