Torrubiano, C., and H. Salinas. “Predicting Stem Volume Tools for Douglas Fir (Pseudotsuga Menziesii (Mirb ) Franco) Located in the Zone of Valdivia”. Revista Bosque, vol. 19, no. 2, Dec. 1998, pp. 11-21, https://revistabosque.org/index.php/bosque/article/view/1254.