P. S. Junior, É. P. Zonta, A. A. Machado, and R. F. de S. Costa, “A method of obtaining the preliminary estimates of the parameters of seazonal growth models”, PAB, vol. 27, no. 12, pp. 1597–1605, Dec. 1992, doi: 10.1590/S1678-3921.pab1992.v27.3809.