@article{10_4153_CMB_2011_061_1,
     author = {Agarwal, Ravi P. and Mustafa, Octavian G.},
     title = {On a {Local} {Theory} of {Asymptotic} {Integration} for {Nonlinear} {Differential} {Equations}},
     journal = {Canadian mathematical bulletin},
     pages = {3--14},
     year = {2012},
     volume = {55},
     number = {1},
     doi = {10.4153/CMB-2011-061-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2011-061-1/}
}