@article{MAN_1963__151_161082,
     author = {R. CARROLL},
     title = {Problems in {Linked} {Operators.} {I.}},
     journal = {Mathematische Annalen},
     pages = {272--282},
     year = {1963},
     volume = {151},
     zbl = {0123.31103},
     url = {http://geodesic.mathdoc.fr/item/MAN_1963__151_161082/}
}