Fractal Properties of Robust Strange Nonchaotic Attractors in Maps of   Two or More Dimensions
  We consider the existence of robust strange nonchaotic attractors (SNA's) in a simple class of quasiperiodically forced systems. Rigorous results are presented demonstrating that the resulting attractors are strange in the sense that their box-counting dimension is N+1 while their information dimension is N. We also show how these properties are manifested in numerical experiments. 
Jong-Won Kim, Sang-Yoon Kim, Brian Hunt, and Edward Ott