On $p$-adic Hard Sphere model with three states on a Cayley tree
  We study $p$-adic model of hard spheres with three states on the Cayley tree. We show that there exist three translation-invariant $p$-adic Gibbs measures and two periodic measures on a Cayley tree of oreder two. 
Otabek Khakimov
math-ph math.FA math.MP