Treatment of ostial renal-artery stenoses with vascular endoprostheses after unsuccessful balloon angioplasty. - Blum,U.; Krumme,B.; Flugel,P.; Gabelmann,A.; Lehnert,T.; Buitrago-Tellez,C.; Schollmeyer,P.; Langer,M. (N Engl J Med, 1997)