@article{10_4064_am30_2_6,
     author = {Piotr Jaworski},
     title = {A geometric point of view
 on mean-variance models},
     journal = {Applicationes Mathematicae},
     pages = {217--241},
     publisher = {mathdoc},
     volume = {30},
     number = {2},
     year = {2003},
     doi = {10.4064/am30-2-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/am30-2-6/}
}