An Indirect Chaining Method for Addressing on Secondary Keys
Methods for entering random access files on
the basis of one key are briefly surveyed.  The 
widely used chaining method, based on a pseudo-random
key transformation, is reviewed in more detail. 
 An efficient generalization of the chaining method
which permits recovery on additional keys is then 
presented.
CACM May, 1961
Johnson, L. R.
