@article{SMJ2_1996_22_2_a3,
     author = {Tsvetkov, D.},
     title = {A {Periodic} {Lotka-Volterra} {System}},
     journal = {Serdica Mathematical Journal},
     pages = {109--116},
     publisher = {mathdoc},
     volume = {22},
     number = {2},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_1996_22_2_a3/}
}