Several problems of plane elasticity theory which can be reduced to different biharmonic boundary value problems are described, and the concept of biharmonic Green functions is discussed.The explicit formula for the particular biharmonic Green function in a circular ringis presented and applied to the solution of the Dirichlet boundary value problem for the bi-Poisson equationfor given f ∈ L p (R; C), p > 2, γ 0 , γ 1 ∈ C(∂R; C).