An Encoding Method for Multifield Sorting and Indexing
Sequences of character strings with an order
relation imposed between sequences are considered. 
 An encoding scheme is described which produces a single,
order-preserving string from a sequence of 
strings.  The original sequence can be recovered from
the encoded string, and one sequence of strings 
precedes another if and only if the encoding of the first
precedes the encoding of the second.  The strings 
may be variable length, without a maximum length restriction,
and no symbols need be reserved for control 
purposes.  Hence any symbol may occur in any string.  The
scheme is useful for multifield sorting, multifield 
indexing, and other applications where ordering
on more than one field is important.
CACM November, 1977
Blasgen, M. W.
Casey, R. G.
Eswaran, K. P.
