@article{SM_2015_206_12_a4,
     author = {R. Ch. Kulaev},
     title = {Disconjugacy of fourth-order equations on graphs},
     journal = {Sbornik. Mathematics},
     pages = {1731--1770},
     publisher = {mathdoc},
     volume = {206},
     number = {12},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2015_206_12_a4/}
}