How should you divide the books into the left, the middle, and the right? This becomes complicated when you have sets of books. If the set goes all the way across the shelf or across two thirds of the shelf then you can assign half of the set to L, half of the set to M and other books will be R. If it goes all the way across the shelf and it happens to fill up the shelf, then you can call part of it L, part of it M, and part of it R. But if you have small sets of two or three books each, you can keep the set in the same shelf location. In other words, arrange the books so that the shelf number is not split up.

This is important because it complicates things when you enter multiple numbers on the database as a result of small sets that are split up.

A larger set that takes up more than two location characters, can be arranged as follows:

Give the entire set the address of the books that are to the left from that set. In other words if this set goes to the M and the R then give it the M.

In the database description of the set write that it expands to the R. In the number of volumes show that it extends past the L.

Sets of books may be interrupted on occasion because of brackets. After all, the set will reach the top of the shelf and under the bracket you will have a book that has is lower in height.