I've been using NotesDeMusique to help me learn how to read music. I have it set up to display four notes at a time, and in bass clef. Pretty simple yet effective. https://play.google.com/store/apps/d...emusique&hl=en
Oh, and it's a freebie, too.
Hofner Group #34, Canadian Club #137, Le Club des Francophones No. 12, Straight-Forward Bassist club #4, Squier Affinity Club #11, 50+ Club #16. Go in, lay it down, and get out.