Correction: Africa's Oesophageal Cancer Corridor: Geographic Variations in Incidence Correlate with Certain Micronutrient Deficiencies. - Torin Schaafsma; Jon Wakefield; Rachel Hanisch; Freddie Bray; Joachim Schüz; Edward J M Joy; Michael J Watts; Valerie McCormack (PLoS ONE, 2015)