The spectrum of the variety of anti-rectangular Abel Grassmann bands
  We prove that the set of all orders of finite algebras in the groupoid variety of anti-rectangular Abel Grassmann bands consists of all powers of four. We also prove that any groupoid anti-isomorphic to a finite or countable anti-rectangular Abel Grassmann band G is isomorphic to G. It is proved that within isomorphism there is only one countable anti-rectangular Abel Grassmann band and that it is isomophic to a proper subgroupoid of itself. 
R. A. R. Monzo
math.RA