Philippines. Bureau of Customs & Philippine Researcg Guide. Customs regulations and rulings. PRG.
芝加哥风格引文Philippines. Bureau of Customs 与 Philippine Researcg Guide. Customs Regulations and Rulings. Quezon City: PRG.
MLA引文Philippines. Bureau of Customs 与 Philippine Researcg Guide. Customs Regulations and Rulings. PRG.
警告：这些引文格式不一定是100％准确.