Lapeña, B. A. (1988). Mathematics achievement of grade six pupils in the public elementary schools of Bacnotan district: An appraisal.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रLapeña, Bona Ami. Mathematics Achievement of Grade Six Pupils in the Public Elementary Schools of Bacnotan District: An Appraisal. 1988.
एमएलए (9वां संस्करण) प्रशस्ति पत्रLapeña, Bona Ami. Mathematics Achievement of Grade Six Pupils in the Public Elementary Schools of Bacnotan District: An Appraisal. 1988.
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