Preface.- Boundary value problems for the singular $p$- and $p(x)$- Laplacian equations in a cone.- Exact and "exact" formulae in the theory of composites.- On a hypercomplex version of the Kelvin solution in linear elasticity.- Viscoelastic behavior of periodontal ligament: stresses relaxation at translational displacement of a tooth root.- Dirichlet type problems in polydomains.- A microscopic model of redistribution of Individuals inside an 'elevator'.-...