@article{10_4153_CJM_1985_019_3,
     author = {Ess\'en, M.},
     title = {Optimization and {\ensuremath{\alpha}-Disfocality} for {Ordinary} {Differential} {Equations}},
     journal = {Canadian journal of mathematics},
     pages = {310--323},
     year = {1985},
     volume = {37},
     number = {2},
     doi = {10.4153/CJM-1985-019-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1985-019-3/}
}