The initial figures 615 are omitted except where they stand alone. Where
figures are followed by a square bracket ], they indicate the position of the book
in the catalogue but not the class where it actually stands in the Library.
Thus Agguzoli: Cantharides 76] is catalogued under 61576, but is
shelved under 615089. The italic letters ƒ and p indicate folio and pamphlet
respectively.