@article{10_4064_cm_64_1_115_119,
     author = {Carlo Cecchini and D\'enes Petz},
     title = {Chain rules for canonical state extensions on von {Neumann} algebras},
     journal = {Colloquium Mathematicum},
     pages = {115--119},
     publisher = {mathdoc},
     volume = {64},
     number = {1},
     year = {1993},
     doi = {10.4064/cm-64-1-115-119},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-64-1-115-119/}
}