Lagumbay และผู้แต่งคนอื่นๆ. 1991. An economic analysis of small rubber plantations in the province of Agusan del Sur, Philippines. Department of Agricultural and Resource Economics, Kasetsart University;
Lagumbay และผู้แต่งคนอื่นๆ. (1991) An economic analysis of small rubber plantations in the province of Agusan del Sur, Philippines . Kasetsart University/Bangkok.
Lagumbay และผู้แต่งคนอื่นๆ. An economic analysis of small rubber plantations in the province of Agusan del Sur, Philippines. . Bangkok:Kasetsart University, 1991.
Lagumbay และผู้แต่งคนอื่นๆ. (1991) An economic analysis of small rubber plantations in the province of Agusan del Sur, Philippines . Kasetsart University/Bangkok.