There will be found at the beginning of many class numbers, a card noting the most reliable books on that subject, and the best of the articles in periodicals, transactions, and collected works with the volume and page where they may be found.  It is hoped to give special prominence to these notes for the guidance of readers, and they will be added as rapidly as other duties allow.

Many subjects will have no sub-section cards at the beginning; some will have no reference cards at the end; and some may have no titles given under the number.  The scheme provides a place for books on all subjects, whether the library has them or not, so where no titles are given under a class number it shows that the library has as yet no books on that subject.

Articles in periodicals and transactions, separate volumes of sets and collections which are located together, if catalogued are put under their proper subject number, but no book number is given with it.  The call number of the book, where they may be found, is always given in the margin preceded by the word IN.  In the same way special chapters in books will sometimes be catalogued, e.g. a card marked 338 IN 331-27, would mean that in the 27 books on 331, Capital and Labor, there was a chapter on 338, Production.