@article{10_4064_sm_95_2_107_118,
     author = {Marek Bo\.zejko},
     title = {Positive-definite kernels, length functions on groups and a noncommutative von {Neumann} inequality},
     journal = {Studia Mathematica},
     pages = {107--118},
     year = {1989},
     volume = {95},
     number = {2},
     doi = {10.4064/sm-95-2-107-118},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-95-2-107-118/}
}