STUDIA SCIENTIARUM MATHEMATICARUM HUNGARICA, cilt.42, sa.2, ss.153-171, 2005 (SCI-Expanded)
In this article we obtain asymptotic formulas of arbitrary order for eigenfunctions and eigenvalues of the nonselfadjoint Sturm-Liouville operators with Dirichlet boundary conditions, when the potential is a summable function. Then using these we compute the main part of the eigenvalues in special cases.