Abdul Wahid, P. R. “BAHASA RESEPTIF DAN BAHASA EKSPRESIF DALAM KOMUNIKASI VERBAL : PEMELAJARAN BAHASA MELAYU KANAK-KANAK SINDROM DOWN: RECEPTIVE AND EXPRESSIVE LANGUAGE IN VERBAL COMMUNICATION: MALAY LANGUAGE AQCUISITION AMONG DOWN SYNDROM CHILDREN”. Jurnal Pengajian Melayu (JOMAS), vol. 19, no. 1, Dec. 2008, pp. 143-66, http://adum.um.edu.my/index.php/JPM/article/view/9731.