A recurrence relation for characters of highest weight integrable   modules for affine Lie algebras
  Using certain results for the vertex operator algebras associated with affine Lie algebras we obtain recurrence relations for the characters of integrable highest weight irreducible modules for an affine Lie algebra. As an application we show that in the simply-laced level 1 case, these recurrence relations give the known characters, whose principal specializations naturally give rise to some multisum Macdonald identities. 
William J. Cook, Haisheng Li, and Kailash C. Misra