@article{DA_2011_18_4_a1,
     author = {A. N. Glebov and D. Zh. Zambalayeva},
     title = {Polynomial algorithm with approximation ratio $7/9$ for maximum {2-PSP}},
     journal = {Diskretnyj analiz i issledovanie operacij},
     pages = {17--48},
     publisher = {mathdoc},
     volume = {18},
     number = {4},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DA_2011_18_4_a1/}
}