@article{ASNSP_1978_4_5_3_567_0,
     author = {Littman, Walter},
     title = {Boundary control theory for hyperbolic and parabolic partial differential equations with constant coefficients},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {567--580},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 5},
     number = {3},
     year = {1978},
     mrnumber = {507002},
     zbl = {0395.35007},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1978_4_5_3_567_0/}
}