1. For Historical development see: a) Strain WH (1976) In: Knoefel PK (ed) International Encyclopedia of Pharmacology and Therapeutics: Radiocontrast Agents, vol 1, sect 76. Pergamon, Oxford, p 1
2. Grainger R (1982) Br J Radiol 55: 1
3. Röntgen WC (1898) Sber Phys-Med Ges Wurzb 137: 132
4. Cameron DF (1918) J Am Med Assoc 70: 754
5. Binz A (1931) J Urol 25: 297