Schneeweiss S, Rassen JA, Brown JS, Rothman KJ, Happe L, Arlett P, Dal Pan W, Goettsch W, Murk W, Wang SV. Graphical depiction of longitudinal study designs in health care databases. Ann Intern Med. 2019 Mar 19;170(6):398-406. doi: 10.7326/M18-3079