Harumdini, M., B. Supriyatno, and R. Sekartini. “Efficacy of Salbutamol-Ipratropium Bromide Nebulization Compared to Salbutamol Alone in Children With Mild to Moderate Asthma Attacks”. Paediatrica Indonesiana, Vol. 52, no. 4, Aug. 2012, pp. 200-8, doi:10.14238/pi52.4.2012.200-8.