@article{10_4064_sm154_3_3,
     author = {Mats Andersson and Sebastian Sandberg},
     title = {The essential spectrum of holomorphic
 {Toeplitz} operators on $H^p$ spaces},
     journal = {Studia Mathematica},
     pages = {223--231},
     year = {2003},
     volume = {154},
     number = {3},
     doi = {10.4064/sm154-3-3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm154-3-3/}
}