Sentence:  In addition, although the  tables in these volumes regularly referred to the 'fueillet, foeullet," or "feullet", the numbers in approximately fifteen percent of these vernacular leaf-numbered manuscripts referred to openings rather than to folios, and in the table of one such book, Brussels BR 9263, the scribe actually became confused as to which unit he was supposed to be <WSD>denumbering</WSD>. 
Meaning of the word marked with <WSD> tags:  To go from a number to the item or element that it indexes.