The material offered here represents a large portion of the author's doctoral dis-
sertation written at the University of Southern California under the direction of
Professor W. A. Harris, Jr. The author wishes to thank Professor Harris for our many
discussions of singular perturbation theory and for his enthusiastic support of this
publication effort. Thanks are also due to Professors K. W. Chang and R. E. O'Malley, Jr.
for their careful reading of the dissertation and for their many helpful suggestions.
The author would also like to acknowledge the generous support provided him by the
U.S.C. Mathematics Department, the State of California and the federal government, in the
form of assistantships, fellowships and grants. Finally, the typist, Miss Jeanette
Figueroa, deserves many thanks for her fine secretarial work.