(1972). Population and heirarchy of cities and municipalities: Bicol region. [s.n.].
芝加哥风格引文Population and Heirarchy of Cities and Municipalities: Bicol Region. [Manila]: [s.n.], 1972.
MLA引文Population and Heirarchy of Cities and Municipalities: Bicol Region. [s.n.], 1972.
警告：这些引文格式不一定是100％准确.