Estupigan, R. (1999). Putting premium on quality tertiary education. Manila Bulletin.
芝加哥风格引文Estupigan, Ruth. "Putting Premium on Quality Tertiary Education." Manila Bulletin 1999.
MLA引文Estupigan, Ruth. "Putting Premium on Quality Tertiary Education." Manila Bulletin, 1999.
警告：这些引文格式不一定是100％准确.