@article{IJAMCS_2001_11_6_a9,
     author = {Grabowski, P. and Callier, F. M.},
     title = {Circle criterion and boundary control systems in factor form: input-output approach},
     journal = {International Journal of Applied Mathematics and Computer Science},
     pages = {1387--1403},
     publisher = {mathdoc},
     volume = {11},
     number = {6},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IJAMCS_2001_11_6_a9/}
}