Where a river is fed by more than one source , it is customary to regard the longest as its source , with other sources considered tributaries .
Where a river is fed by more than one source , it is usual to regard the highest as its source .
Where a river is fed by more than one source , it is usual to regard the highest as its source .
Simplify this text: Where a river is fed by more than one source , it is customary to regard the longest as its source , with other sources considered tributaries . Output: