On the energy dependence of hadronic $B_c$ production
  An estimate is presented of the production cross section of $B_c$ mesons between threshold and LHC energies using lowest-order perturbation theory and non-relativistic bound state approximation. It is shown that the ratio of the production cross sections for $B_c$ mesons and for $b$ quarks varies strongly with energy. 
K. Kolodziej and R. R\"uckl