James L. Massey Ueli M. Maurer Muzhong Wang Non-Expanding, Key-Minimal, Robustly-Perfect, Linear and Bilinear Ciphers. 237-247 http://link.springer.de/link/service/series/0558/bibs/0304/03040237.htm 1987 EUROCRYPT db/conf/eurocrypt/eurocrypt87.html#MasseyMW87