Lopez-Islas, Jose Rafael2014-11-032014-11-031992-05-01http://hdl.handle.net/20.500.14446/13504application/pdfCopyright is held by the author who has granted the Oklahoma State University Library the non-exclusive right to share this material in its institutional repository. Contact Digital Library Services at lib-dls@okstate.edu or 405-744-9161 for the permission policy on the use, reproduction or distribution of this material.text