http://arxiv.org/abs/gr-qc/0609004 Calculation of the Cosmological Constant by Unifying Matter and Dark Energy Torsten Asselmeyer-Maluga, Helge Rosé 23 pages, submitted to Adv. Theor. Math. Phys "We show that the differential-geometric description of matter by differential structures of spacetime leads to a unifying model of the three types of energy in the cosmos: matter, dark matter and dark energy. Using this model we are able to calculate the value of the cosmological constant with Lambda = sqrt(14/27) 8 pi G/c^2 rho_obs = 1.4 10^-52 m^-2."