Possible Clues:

• Mark made by pressing or stamping surface
• Mark made by pressing or stamping
• If I am pressed, just put a stamp on it
• Mark left by stamping a surface
• Publisher's name on title-page of book
• Mark produced by pressure
• Setter's volume includes right to show publisher's identity
• Stamp (with sense of identity)
• Fix in the mind; stamp
• Pair invested in single unused stamp