@article{10_4064_sm_33_2_193_196,
     author = {B. Pettis},
     title = {On {Nikaid\^o's} proof of the invariant mean-value theorem},
     journal = {Studia Mathematica},
     pages = {193--196},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {1969},
     doi = {10.4064/sm-33-2-193-196},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-33-2-193-196/}
}