The importance of studying the renin-angiotensin-aldosterone system in essential arterial hypertension in clinical practise. Activity of the renin-angiotensin-aldosterone system during treatment of hypertension with ACE-inhibitors and beta-blockers. - Hrnciar,J.; Hrnciarova,M.; Lepej,J.; Okalova,D.; Kreze,A.; Chamulova,M. (Vnitr Lek, 1994)