“…The first example of a non-toral nilmanifold admitting an Anosov automorphism was described by S. Smale ([20]). For many years only relatively few examples appeared in the literature, but in recent years families of nilmanifolds with Anosov automorphisms have been constructed showing that a complete classification does not seem to be possible (see [11,2,4,5,6,7,13,14,16,18,21]).…”