@article{boyd:1998:asl,
    author = {Boyd, John P. and Natarov, Andrei},
     title = {A {S}turm-{L}iouville eigenproblem of the fourth kind: A
              critical latitude with equatorial trapping},
   journal = {Stud. Appl. Math.},
  fjournal = {Studies in Applied Mathematics},
    volume = {101},
      year = {1998},
    number = {4},
     pages = {433–455},
      issn = {0022-2526},
   mrclass = {34L40 (34B24 34E05 76B65)},
  mrnumber = {MR1706176 (2000d:34182)},
       doi = {10.1111/1467-9590.00100},
     zblno = {1020.34080}}