Suppose that one wishes to replace words in a list by abbreviations in order to save space. If one allows abbreviations of variable length, a very simple rule is: use as many letters as needed to ensure that a word is not confused with any other word. For example, the states Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware... can be replaced by ALAB, ALAS, ARI , ARK, CA, COL, CON, D...
Eckler, A. Ross
"Labeling A List With Unique Identifiers,"
Word Ways: Vol. 33
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol33/iss3/15