Related Clues:
- Twenty-vol. reference work
- Voluminous lexicological work: Abbr.
- Something besides the ltr.
- Mailed doc.
- Multivolume Brit. reference
- Ref. work with more than 300,000 entries
- Atlas shelfmate: Abbr.
- Pub. with over 300,000 entries
- Exhaustive ref.
- Work started by London's Philological Soc.
- RSVP card, e.g.
- Business letter letters
- Its Vol. XVI is "Soot-Styx"
- Ltr. add-in
- Ref. work with online subscriptions