@article{MZM_2013_93_5_a7,
     author = {V. A. Kolmykov},
     title = {Nonnegativity for {Cartan--Tits} and {Kac--Moody} {Forms}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {736--740},
     publisher = {mathdoc},
     volume = {93},
     number = {5},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2013_93_5_a7/}
}