The Cosmological Constant Emerging From Local Poincare Invariance
  The Poincare Gauge Theory of gravitation with a Lagrangian quadratic in the field strengths is applied to a classical cosmological model. It predicts a constant value of the non-riemannian curvature scalar, which acts as a cosmological constant. As the value of the scalar depends on the context, vacuum solutions may differ from the predictions based on Einstein's constant. The corresponding deviations from General Relativity are discussed on the basis of exact solutions for the field of a mass point. 
Paul von der Heyde