@article{EJDE_2011__2011__a27,
     author = {Littlejohn, Lance L. and Zettl, Anton},
     title = {The {Legendre} equation and its self-adjoint operators},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2011},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2011__2011__a27/}
}