Equation of state of additive hard-disk fluid mixtures: A critical   analysis of two recent proposals
  A detailed analysis of two different theoretical equations of state for a binary mixture of additive hard disks [C. Barrio and J. R. Solana, Phys. Rev. E 63, 011201 (2001); A. Santos, S. B. Yuste and M. Lopez de Haro, Mol. Phys. 96, 1 (1999)], including their comparison with Monte Carlo results, is carried out. It is found that both proposals, which require the equation of state of the single component system as input, lead to comparable accuracy when the same input is used in both, but the one advocated by Santos et al. is simpler and complies with the exact limit in which the small disks are point particles. 
M. Lopez de Haro, S. B. Yuste, and A. Santos