E. P. B. Guidang, C. Q. Alagao, M. B. Alvarez, J. B. T. Carreon, M. A. Alcalde, and L. L. Quintinita, “Interactive Ilokano Mother Tongue-Based Courseware for Grade 1 Mathematics: Development and Usability”, IRJ, vol. 6, no. 1, pp. 46–60, Oct. 2015, doi: 10.7719/irj.v6i1.362.