Letran, C. C. (1976). An analysis of the use of the process approach for teaching grades I and II elementary science in the public schools in the Division of Isabela during the school year 1969-1970. University of the Philippines Library.
Chicago-viite (17. p.)Letran, Carmen Collado. An Analysis of the Use of the Process Approach for Teaching Grades I and II Elementary Science in the Public Schools in the Division of Isabela During the School Year 1969-1970. Quezon City: University of the Philippines Library, 1976.
MLA-viite (9. p.)Letran, Carmen Collado. An Analysis of the Use of the Process Approach for Teaching Grades I and II Elementary Science in the Public Schools in the Division of Isabela During the School Year 1969-1970. University of the Philippines Library, 1976.