@article{EJDE_2011__2011__a91,
     author = {Mingarelli,  Angelo B.},
     title = {A note on {Sturm-Liouville} problems whose spectrum is the set of prime numbers},
     journal = {Electronic journal of differential equations},
     year = {2011},
     volume = {2011},
     zbl = {1231.34045},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2011__2011__a91/}
}