Cotes, J. E., Dabbs, J. M., Hall, A. M., Axford, A. T., and Laurence, K. M. (1973). Thorax, 28, 709-715. Lung volumes, ventilatory capacity, and transfer factor in healthy British boy and girl twins. Normal values are reported for the lung volumes, ventilatory capacity, and transfer factor of 212 healthy British twin children aged 8 to 16 years. The boys and the girls share a common relationshi...