G. Hammerlin & K.-H. Hoffmann ed..Improperly posed problems and their numerical treactment：Conference held at the Mathematisches Forschungsinstitut, Oberwolfach, 1982.Birkhauser,1983.
G. B. Davis & T. R. Hoffmann.：a structured,disciplined style based on 1977 American National Standard FORTRAN and compatible with WATFOR,WATFIV,WATFIVS ,and M77 FORTRAN compilers;FORTRAN 77.McGraw-Hill,1983.
：a structured,disciplined style based on 1977 American National Standard FORTRAN and compatible with WATFOR,WATFIV,WATFIVS ,and M77 FORTRAN compilers;FORTRAN 77
