Subong, N. L. (1971). The teaching difficulties of elementary school teachers of modern mathematics in some selected public schools in Manila.
Lua i Stíl Chicago (17ú heag.)Subong, Nieva Liberia. The Teaching Difficulties of Elementary School Teachers of Modern Mathematics in Some Selected Public Schools in Manila. 1971.
Lua MLA (9ú heag.)Subong, Nieva Liberia. The Teaching Difficulties of Elementary School Teachers of Modern Mathematics in Some Selected Public Schools in Manila. 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.