The four students purchased small items in other parts of the store and kept their receipts, then sat down at the lunch counter and asked to be served.. 
et herring f.G., General Chemistry (8ẹ edition, prentice-Hall 2002) awọn ẹgbẹ elimẹ́ńtì kẹ́míkàtabili idasiko awọn elimẹ́ńtì.. 