For the structure functions of the quark propagator, the asymptotic behavior
is obtained for general, linear, covariant gauges, and in all directions of the
complex k2-plane. Asymptotic freedom is assumed. Corresponding previous
results for the gauge field propagator are important in the derivation. Except
for coefficients, the leading asymptotic terms are determined by one-loop or by
two-loop information, and are gauge independent. Various sum rules are derived.Comment: 15 pages, Late