@article{AM2_1977__16_136678,
     author = {V. Hiris and M. Megan},
     title = {Controllability of linear systems and a boundary value problem.},
     journal = {Aequationes mathematicae},
     pages = {81--92},
     publisher = {mathdoc},
     volume = {16},
     year = {1977},
     zbl = {0385.93006},
     url = {http://geodesic.mathdoc.fr/item/AM2_1977__16_136678/}
}