1. Burn, J. H., Rand, M.: Sympathetic postganglion mechanism. Nature (Lond.) 184, 163?165 (1959).
2. DeRobertis, E. D. P., Iraldi, A. P. de: A pleurivascular component in adrenergic nerve endings. Anat. Rec. 139, 299 (1961).
3. Esterhuizen, A. C., Graham, J. D. P., Lever, J. D., Spriggs, T. L. B.: Catecholamine and acetylcholinesterase distribution in relation to noradrenaline release. An enzyme histochemical and autoradiographic study on the innervation of the cat nictitating muscle. Brit. J. Pharmacol. 32, 46?56 (1968).
4. Graham, J. D. P., Lever, J. D., Spriggs, T. L. B.: An examination of adrenergic axons around pancreatic arterioles of the cat for the presence of acetylcholinesterase by high resolution autoradiographic and histochemical methods. Brit. J. Pharmacol. 33, 15?20 (1965).
5. H�kfelt, T., Nilsson, O.: The relationship between nerves and smooth muscle cells in the rat Iris: II. The sphincter muscle. Z. Zellforsch. 66, 848?853 (1965).