Beekman, C.S.*, Neiderhiser, J.M., Buss, K.A., Loken, E., Moore, G., Leve, L.D., Ganiban, J.M., Shaw, D.S., & Reiss, (2015). The development of early profiles of temperament: characterization, continuity, and etiology. Child Development, 86(6), 1794-1811. doi: 10.1111/cdev.12417
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562331/