@article{10_4064_sm158_3_3,
     author = {Bertram Yood},
     title = {Ascent, descent and roots of {Fredholm} operators},
     journal = {Studia Mathematica},
     pages = {219--226},
     publisher = {mathdoc},
     volume = {158},
     number = {3},
     year = {2003},
     doi = {10.4064/sm158-3-3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm158-3-3/}
}