The lower mass function of young open clusters
  We report new estimates for the lower mass function of 5 young open clusters spanning an age range from 80 to 150 Myr. In all studied clusters, the mass function across the stellar/substellar boundary (~0.072 Mo) and up to 0.4 Mo is consistent with a power-law with an exponent alpha of -0.5 +/- 0.1, i.e., dN/dM ~ M**(-0.5). 
J. Bouvier, E. Moraux, J.R. Stauffer, D. Barrado y Navascues, J.-C.   Cuillandre