Related Clues:

• Staff figures
• Marginalia, e.g.
• Written reminders
• Memos
• Lecture record
• Uses a cell phone, maybe
• School books
• Contacts via cell phone, in a way
• Short messages
• Speaker's aids
• Music symbols
• Contacts by phone, in a way
• Brief letters
• Flagship product from 21-Down
• Explanatory material