Svetlana N. Yanushkevich Denis V. Popel Vlad P. Shmerko V. Cheushev Radomir S. Stankovic Information Theoretic Approach to Minimization of Polynomial Expressions over GF(4). 265- 2000 ISMVL http://computer.org/proceedings/ismvl/0692/06920265abs.htm db/conf/ismvl/ismvl2000.html#YanushkevichPSCS00