"Lung diffusing capacity for nitric oxide measured by two commercial devices: a randomised crossover comparison in healthy adults". Thomas Radtke, Quintin de Groot, Sarah R. Haile, Marion Maggi, Connie C.W. Hsia and Holger Dressel. ERJ Open Res 2021; 7: 00193-2021. Issue 3 (13th September 2021) - Unknown