BUTTERWORTH, J. W.; SPRING, K. C. F. Column design
. Bulletin of the New Zealand Society for Earthquake Engineering, [S. l.], v. 18, n. 4, p. 344–350, 1985. DOI: 10.5459/bnzsee.18.4.344-350. Disponível em: https://bulletin.nzsee.org.nz/article/view/856. Acesso em: 7 may. 2026.