Estupigan, R. (1997). Secrets of effective study habits. Manila Bulletin.
芝加哥风格引文Estupigan, Ruth. "Secrets of Effective Study Habits." Manila Bulletin 1997.
MLA引文Estupigan, Ruth. "Secrets of Effective Study Habits." Manila Bulletin, 1997.
警告：这些引文格式不一定是100％准确.