Treatment of Ostial Renal-Artery Stenoses with Vascular Endoprotheses after Unsuccessful Balloon Angioplasty. - Blum,U.; Krumme,B.; Flügel,P.; Gabelmann,A.; Lehnert,T.; Buitrago-Tellez,C.; Schollmeyer,P.; Langer,M. (N Engl J Med, 1997)