@article{COCV_1999__4__609_0,
     author = {Zhou, Yishao},
     title = {On the phase portrait of the fast filtering algorithms},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {609--630},
     publisher = {EDP-Sciences},
     volume = {4},
     year = {1999},
     mrnumber = {1746170},
     zbl = {0937.93050},
     language = {en},
     url = {http://archive.numdam.org/item/COCV_1999__4__609_0/}
}