Eric Walker added Extensively drug-resistant tuberculosis (XDR-TB), 2019-07 London School of Hygiene & Tropical Medicine study on MDR-TB and 2020-07 Culture Conversion in Patients Treated with Bedaquiline and/or Delamanid: A Prospective Multi-country Study and a number of links to Multidrug-resistant tuberculosis (MDR-TB), and added Multidrug-resistant tuberculosis (MDR-TB) to Drug-resistant tuberculosis (DR-TB)