A ? following a word or entry signifies _probably_.  (6c

_Brackets_ inclose words added to titles or imprints or changed in

form.  (6d

Arabic _figures_ are to be used rather than Roman; but small capitals

may be used after the names of sovereigns, princes, and popes.  (6e

A list of _abbreviations_ to be used was given in the _Library

journal_, 3: 16–20.  (6f