Crossword clues for Reference book abbr. 4 letters:ENCYReference book: Abbr.IBIDReference book abbr.DICTReference book (abbr.)OEDStandard reference book: Abbr.CYCReference book: Abbr.OEDReference book: Abbr.OEDMulti-volume reference book (abbr.)ETSEQReference book abbr.ENCReference book: Abbr.ENCYSSets of reference books: Abbr.