1. Medica Sur Clinic & Foundation; Puente de Piedra 150 Mexico City Mexico 14050
2. National Institute of Public Health; Tobacco Research Department; 7a Cerrada de Fray Pedro de Gante #50 Col Seccion XVI, Tlalpan Mexico City Mexico City Mexico 14000
3. Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán; Department of Gastroenterology; Mexico City Distrito Federal Mexico 1400
4. Enhance Reviews Ltd; 5 Percy Street, Office 4 London UK W1T 1DG