1. On close-packed double error-correcting codes on p symbols;Engelman;IRE Trans. Inform. Theory,1961
2. Notes on digital coding;Golay,1949
3. On the diophantine equation ay2 + by + c = dxn;Landau,1921
4. Some properties of non-binary error-correcting codes;Lee;IRE Trans. Inform. Theory,1958