Column 1 - Town, library and shelfmark are generally given in full or lightly abbreviated.
Only four abbreviations according to the RISM convention are used:
Cu = Cambridge, University Library
Lbl = London, British Library
Mu = Manchester, John Rylands University Library
Ob = Oxford, Bodleian Library
Column 2 - Type of book. Sometimes the type of book is qualified with an added descriptor when it falls into a commonly understood sub-group, such as a book of hours of the Sarum type: "hours (Sarum)". Consistency in this respect has not (yet) been achieved, however, so that "Sarum", for example, can also appear in Column 3, describing the provenance, which is, strictly speaking, incorrect. Most of the terms used are given below.
Column 3 - Abbreviations for the religious orders:
Column 4 - a date followed by "i" means near the beginning of or early in a particular century; "m" means in the middle; "x" means near the end of or late in a particular century; "ca." = circa (about). "1/2" means first half of the century, "2/2" second half, "3/4" third quarter, and so on.