Mahmoud, N.F., Amin, F.M. and Ayed, M.M.A. 2021. Effectiveness of instructional guidelines implementation on mothers’ knowledge and practice regarding their children with methylmalonic acidemia. International journal of health sciences. 5, S2 (Dec. 2021), 912–930. DOI:https://doi.org/10.53730/ijhs.v5nS2.13911.