@article{IVM_2007_8_a7,
     author = {V. \`E. Gheit and N. Zh. Gheit},
     title = {Nonnegativity criteria for fourth degree polynomials on the axis},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {70--73},
     year = {2007},
     number = {8},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2007_8_a7/}
}