Related Clues:

• Insert of a sort: Abbr
• Ref. last published in 1989
• Webster's relative, for short
• Britannica, for one: Abbr
• Brit. reference book
• Ref. with no substitute
• Champs' prize on the UK game show ''Countdown''
• Env. stuffing
• Voluminous ref
• S.A.S.E., e.g.: Abbr
• Its "Concise" version has more than 1,700 pgs
• Work requiring oversized shelves, briefly
• It took 70 years to complete, in brief
• Ref. with no proper nouns in its earliest edition
• "Half-caf" was added to it in 2012