Zovala zamankhwala ndi chida chofunikira kwambiri pakuwongolera mabala. Kukambilana zobvala zachipatala ndi mutu wamuyaya kwa akatswiri a bala. Komabe, pali mitundu yambiri yamavalidwe azachipatala pamsika, mitundu yopitilira 3000, ndikofunikira kusankha zovala zoyenera zamankhwala moyenera.
Werengani zambiri