@article{EJDE_1997__1997__a13,
     author = {Ignatyev,  Alexander O.},
     title = {Stability of a linear oscillator with variable parameters},
     journal = {Electronic journal of differential equations},
     year = {1997},
     volume = {1997},
     zbl = {0889.34043},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_1997__1997__a13/}
}