Nam Sam River
Chu River ( name in Vietnam , ) or Nam Sam River ( name in Laos ) is the largest tributary of Ma River . 
<triplet> Nam Sam River <subj> Laos <obj> country <subj> Ma River <obj> mouth of the watercourse <triplet> Ma River <subj> Vietnam <obj> country <subj> Nam Sam River <obj> tributary <subj> Laos <obj> country