  We study the collective states formed by two-dimensional electrons in Landau
levels of index $n\ge 2$ near half-filling. By numerically solving the
self-consistent Hartree-Fock (HF) equations for a set of oblique
two-dimensional lattices, we find that the stripe state is an anisotropic
Wigner crystal (AWC), and determine its precise structure for varying values of
the filling factor. Calculating the elastic energy, we find that the shear
modulus of the AWC is small but finite (nonzero) within the HF approximation.
This implies, in particular, that the long-wavelength magnetophonon mode in the
stripe state vanishes like $q^{3/2}$ as in an ordinary Wigner crystal, and not
like $q^{5/2}$ as was found in previous studies where the energy of shear
deformations was neglected.
