Al-Hadabi, Abdulsalam Sulaiman Dawood. “Understanding Acid and Base Concepts Among Chemistry and Biology Pre-Service Teachers at Faculty of Education in Amran University–Yemen”. Arab Journal for Sciences and Research Publishing 2, no. 6 (September 30, 2016): 233. Accessed December 20, 2025. https://ajsrp.ojsexpert.com/index.php/ajsrp/article/view/1789.