  We investigate asymptotic behavior of solutions for nonlocal elliptic
boundary value problems in plane angles and in ${\mathbb R}^2\backslash\{0\}$.
Such problems arise as model ones when studying asymptotics of solutions for
nonlocal elliptic problems in bounded domains. We obtain explicit formulas for
the asymptotic coefficients in terms of eigenvectors and associated vectors of
both adjoint nonlocal operators (acting in spaces of distributions) and
formally adjoint (with respect to the Green formula) nonlocal problems.
