@article{kwon:2006:cdo,
    author = {Kwon, K. H. and Littlejohn, L. L. and Yoon, G. J.},
     title = {Construction of differential operators having
              {B}ochner-{K}rall orthogonal polynomials as eigenfunctions},
   journal = {J. Math. Anal. Appl.},
  fjournal = {Journal of Mathematical Analysis and Applications},
    volume = {324},
      year = {2006},
    number = {1},
     pages = {285–303},
      issn = {0022-247X},
     coden = {JMANAK},
   mrclass = {33C45 (34L10 47E05)},
  mrnumber = {MR2262472},
       doi = {10.1016/j.jmaa.2005.11.059},
     zblno = {1121.34016}}