Systems and implementation science should be part of the COVID-19 response in low resource settings by English, M, Moshabela, M, Nzinga, J, Barasa, E, Tsofa, B, Marchal, B, Kruk, ME

Realist RCTs of complex interventions - an oxymoron. by Marchal, B, Westhorp, G, Wong, G, Van Belle, S, Greenhalgh, P, Kegels, G, Pawson, R

Can "realist" randomised controlled trials be genuinely realist? by Van Belle, S, Wong, G, Westhorp, G, Pearson, M, Emmel, N, Manzano, A, Marchal, B

What's in a realist configuration? Deciding which casual configurations to use, how, and why by De Weger, E, Van Vooren, NJE, Wong, G, Dalkin, S, Marchal, B, Drewes, HW, Baan, CA

What role can health policy and systems research play in supporting responses to COVID-19 that strengthen socially just health systems? by Gilson, L, Marchal, B, Ayepong, I, Barasa, E, Dossou, J-P, George, A, Guinaran, R, Maceira, D, Molyneux, S, Prashanth, NS, Schneider, H, Shawar, Y, Shiffman, JR, Sheikh, K, Spicer, N, Van Belle, S, Whyle, E