Amolat, H. M., & Sison, W. M. (1977). Proposed instructional materials on the teaching of multiplication to educable mentally retarded children at the intermediate level. College of Education, University of the Philippines Diliman.

Amolat, Herminia Macaraig, and Waldetrudes Montojo Sison. Proposed Instructional Materials on the Teaching of Multiplication to Educable Mentally Retarded Children at the Intermediate Level. Quezon City: College of Education, University of the Philippines Diliman, 1977.

Amolat, Herminia Macaraig, and Waldetrudes Montojo Sison. Proposed Instructional Materials on the Teaching of Multiplication to Educable Mentally Retarded Children at the Intermediate Level. College of Education, University of the Philippines Diliman, 1977.