  The structure of the BP<n>-cohomology of elementary abelian p-groups is
studied, obtaining a presentation expressed in terms of BP-cohomology and mod-p
singular cohomology, using the Milnor derivations.
  The arguments are based on a result on multi-Koszul complexes which is
related to Margolis's criterion for freeness of a graded module over an
exterior algebra.
