@article{leeb:1979:acm,
    author = {Leeb, W. R.},
     title = {Algorithm 537: Characteristic values of
              {M}athieu's differential equation},
   journal = {ACM Trans. Math. Software},
    volume = {5},
      year = {1979},
    number = {1},
     pages = {112–117},
      issn = {0098-3500},
       doi = {10.1145/355815.355824},
     links = {\GAMSmodule{TOMS}{537}{8576}}}