@article{1077475191,
author = {Haltiner, G. J.},
title = {The theory of linear differential systems based upon a new
definition of the adjoint},
journal = {Duke Math. J.},
volume = {15},
number = {1},
year = {1948},
pages = { 893-920},
language = {en},
url = {http://dml.mathdoc.fr/item/1077475191}
}
Haltiner, G. J. The theory of linear differential systems based upon a new
definition of the adjoint. Duke Math. J., Tome 15 (1948) no. 1, pp. 893-920. http://gdmltest.u-ga.fr/item/1077475191/