Yang, Z., Brentnall, A. R., Cuzick, J. and Sasieni, P. (2012) “Estimating the Complier Average Causal Effect for Exponential Survival in the Presence of Mid-Trial Switching”, International Journal of Statistics in Medical Research, 1(2), pp. 84–90. doi: 10.6000/1929-6029.2012.01.02.01.