Oxley-Oxland, JV, et al. “The Characteristics and Costs of Severe Theophylline Toxicity in a Tertiary Critical Care Unit in Eastern Cape Province, South Africa”. South African Medical Journal, vol. 112, no. 11, Nov. 2022, pp. 866-70, https://doi.org/10.7196/SAMJ.2022.v112i11.16453.