  This research summarizes work done by myself (Nucl.Phys.{\bf A641}
(1998)461), or in collaboration with R. M. Davidson (Phys.Lett.{\bf
B348}(1995)163) and H. Weigel and L. Gamberg (Nucl.Phys.{\bf B560}(1999)xx). I
will discuss several topics related with the computation of structure functions
in the quark model in general and its perturbative evolution. In particular, I
address this topic in the Nambu-Jona-Lasinio model of hadrons, where the
nucleon is constructed as a soliton. I show that the handling of the
regularization procedure is crucial in order to obtain exact scaling in the
Bjorken limit and fulfillment of sum rules. I also include some problems
concerning the general validity of quark model calculations.
