Filtra

Petrolingua Ltd. (San Pietroburgo / Northwestern Federal District / Russia)
Swiss Center Ltd. (San Pietroburgo / Northwestern Federal District / Russia)
Nevsky Institute of Language & Culture (San Pietroburgo / Northwestern Federal District / Russia)
INTEX (Surgut / Ural Federal District / Russia)
International Language School Cosmopolitan (Novosibirsk / Siberian Federal District / Russia)