@article{IJAMCS_2003_13_2_a1,
     author = {Zerrik, E. H. and Bourray, H.},
     title = {Gradient {Observability} for {Diffusion} {Systems}},
     journal = {International Journal of Applied Mathematics and Computer Science},
     pages = {139--150},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IJAMCS_2003_13_2_a1/}
}