@article{amos:1990:aec,
    author = {Amos, Donald E.},
     title = {Algorithm 683: {A} portable {FORTRAN} subroutine for exponential
              integrals of a complex argument},
   journal = {ACM Trans. Math. Software},
  fjournal = {Association for Computing Machinery. Transactions on
              Mathematical Software},
    volume = {16},
      year = {1990},
    number = {2},
     pages = {178–182},
      note = {Double- and single-precision Fortran, maximum accuracy 18S or 14S.},
      issn = {0098-3500},
     coden = {ACMSCU},
   mrclass = {65D20 (65Y10)},
  mrnumber = {MR1158087 (92k:65026)},
       doi = {10.1145/78928.78934},
     links = {\GAMSmodule{TOMS}{683}{8725}},
     zblno = {0900.65029}}