@article{CMUC_1996__37_1_a4,
     author = {Ricker, Werner J.},
     title = {Sequential closures of $\sigma$-subalgebras for a vector measure},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {91--97},
     publisher = {mathdoc},
     volume = {37},
     number = {1},
     year = {1996},
     mrnumber = {1396162},
     zbl = {0877.28011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1996__37_1_a4/}
}