Hi, Hai
As far as I remember some of the four characters in the film were from
families of Russian immigrants, that's why they sang Katiusha.
BTW, I remember the vietnamese translation of the title what "Nhu+~ng
ngu+o+`i sa(n hu+o+u", the^' ne^n to^i mo+'i tha('c ma('c kho^ng hie^?u
tie^'ng Anh co' pha^n bie^.t hu+o+u voi+'i nai kho^ng nhi? :-)
Best,
Trung