(1972). Area of influences: Road network of the Bicol region. [s.n.].
Chicagoスタイル(17版)引用形式Area of Influences: Road Network of the Bicol Region. [Manila]: [s.n.], 1972.
MLA(9版)引用形式Area of Influences: Road Network of the Bicol Region. [s.n.], 1972.
警告: この引用は必ずしも正確ではありません.