  As it was shown earlier [Dzero, Gor'kov, and Zvezdin, J. Phys.:Condens.
Matter 12, L711 (2000)] the properties of the first-order valence phase
transition in YbInCu4 in the wide range of magnetic fields and temperatures are
perfectly described in terms of a simple entropy transition for free Yb ions.
Within this approach, the crystal field effects have been taken into account
and we show that the phase diagram in the $B-T$ plane acquires some anisotropy
with respect to the direction of an external magnetic field.
