The Minimization of Spatially-Multiplexed Character Sets
The paper describes a technique for compacting
character sets in a digital computer while retaining 
fast access to individual bits.  It considers the problem
of minimizing the storage needed to contain 
such tables.  Reduction techniques are developed, and
the problem is shown to reduce to a covering problem.
CACM June, 1974
Gimpel, J. F.
