Kahan, Brennan C., Hall, Sophie S., Beller, Elaine M., Birchenall, Megan, Elbourne, Diana, Juszczak, Edmund, Little, Paul, Fletcher, John, Golub, Robert M., Goulao, Beatriz, Hopewell, Sally, Islam, Nazrul, Zwarenstein, Merrick, Chan, An-Wen, Montgomery, Alan A., "Consensus Statement for Protocols of Factorial Randomized Trials: Extension of the SPIRIT 2013 Statement", JAMA Network Open, 2023