@article{AIF_2014__64_6_2503_0,
     author = {Knop, Friedrich},
     title = {Spherical roots of spherical varieties},
     journal = {Annales de l'Institut Fourier},
     pages = {2503--2526},
     publisher = {Association des Annales de l{\textquoteright}institut Fourier},
     volume = {64},
     number = {6},
     year = {2014},
     doi = {10.5802/aif.2919},
     zbl = {06387346},
     mrnumber = {3331173},
     language = {en},
     url = {http://archive.numdam.org/articles/10.5802/aif.2919/}
}