Dean, Sharon M.2014-03-142014-03-141991-05-05etd-01202010-020221http://hdl.handle.net/10919/40704No abstract provided by author.iii, 21 leavesBTDapplication/pdfenIn CopyrightLD5655.V851 1991.D436SelfMajor paperhttp://scholar.lib.vt.edu/theses/available/etd-01202010-020221/