Löwhagen, G., Brorson, J. and Kaijser, B. (1983) “Penicillin concentrations in cerebrospinal fluid and serum after intramuscular, intravenous, and oral administration to syphilitic patients”, Acta Dermato-Venereologica, 63(1), pp. 53–57. doi: 10.2340/00015555635357.