Dietary nitrate and nitrite levels in an endemic upper gastrointestinal (esophageal and gastric) cancer region of Turkey - TÜRKDOĞAN, M. Kürşat; TESTERECİ, Haluk; AKMAN, Nevzat; KAHRAMAN, Tahir; KARA, Kazım; TUNCER, İlyas; UYGAN, İsmail (Turkish Journal of Gastroenterology, 2003)