@article{MAN_1994__299_4_165212,
     author = {D.E. Edmunds and H. Triebel},
     title = {Eigenvalue distributions of some degenerate elliptic operators: an approach via entropy numbers.},
     journal = {Mathematische Annalen},
     pages = {311--340},
     publisher = {mathdoc},
     volume = {299},
     number = {4},
     year = {1994},
     zbl = {0804.35097},
     url = {http://geodesic.mathdoc.fr/item/MAN_1994__299_4_165212/}
}