Formacion, P. S. Inquiry slides for teaching ecology in the elementary grades.
芝加哥风格引文Formacion, Placida S. Inquiry Slides for Teaching Ecology in the Elementary Grades. Quezon City, 1973.
MLA引文Formacion, Placida S. Inquiry Slides for Teaching Ecology in the Elementary Grades.
警告：这些引文格式不一定是100％准确.