Repeated measurements designs are concerned with scientific experiments in which each experimental unit is assigned more than once to a treatment, either different or identical. It is shown that a family of balanced repeated measurements designs which are very popular among experimenters are universally optimal in a relatively large class of competing designs.
"Repeated Measurements Designs, II." Ann. Statist. 6 (3) 619 - 628, May, 1978. https://doi.org/10.1214/aos/1176344206