@article{vedeler:1950:mes,
    author = {Vedeler, Georg},
     title = {A {M}athieu equation for ships rolling among waves. {I}, {II}},
   journal = {Norske Vid. Selsk. Forh., Trondheim},
    volume = {22},
      year = {1950},
    number = {25–26},
     pages = {113–123},
   mrclass = {76.1X},
  mrnumber = {MR0034660 (11,624b)},
mrreviewer = {J. V. Wehausen},
     zblno = {0036.08104}}