Weyl Group Invariance and p-brane Multiplets
  In this paper, we study the actions of the Weyl groups of the U duality groups for type IIA string theory toroidally compactified to all dimensions $D\ge 3$. We show how these Weyl groups implement permutations of the field strengths, and we discuss the Weyl group multiplets of all supersymmetric $p$-brane solitons. 
H. Lu, C.N. Pope and K.S. Stelle