@article{10_4064_sm168_1_6,
     author = {J. H. Qiu},
     title = {Ekeland's variational principle in {Fr\'echet} spaces
 and the density of extremal points},
     journal = {Studia Mathematica},
     pages = {81--94},
     publisher = {mathdoc},
     volume = {168},
     number = {1},
     year = {2005},
     doi = {10.4064/sm168-1-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm168-1-6/}
}