Safira, N., E. M. P. Dewi, and H. Hamid. “EFEKTIVITAS PENERAPAN PICTURE EXCHANGE COMMUNICATION SYSTEM (PECS) TERHADAP KEMAMPUAN BERBICARA EKSPRESIF PADA ANAK DOWN SYNDROME”. Al Asma : Journal of Islamic Education, Vol. 3, no. 1, May 2021, pp. 50-63, doi:10.24252/asma.v3i1.21072.