Higher order Painlev\'e equations of type $A^{(1)}_l$
  A series of systems of nonlinear equations with affine Weyl group symmetry of type $A^{(1)}_l$ is studied. This series gives a generalization of Painlev\'e equations $P_{IV}$ and $P_{V}$ to higher orders. 
Masatoshi Noumi and Yasuhiko Yamada