The paper applies a general method developed by the authors in another publication (novel applications of Betti-Rayleigh reciprocal theorem) to derive the correct set of boundary conditions for arbitrarily prescribed edge data [J. Elasticity 14, 27-64 (1984; Zbl 0536.73047)]. A semi- infinite plate with edge-data prescribed along the only edge and axisymmetric bending of a circular simply supported plate loaded by uniform pressure are handled in detail. It is shown that the stresses in a plate are not in general uniquely determined solely by the stress resultants and couples acting at the edge.