Emmanuel, J. A., Gatmaytan, G. B., Kalaw Jr., M. T., Leonen, M. F., Luna ,Maria Paz G., & Paredes, J. J. (1993). Lecture-Series on the Philippine Environment in the 21st century: Issues and concerns. UP Law Center, Institute of International Legal Studies.

Emmanuel, Jorge A., Gus B. Gatmaytan, Maximo T. Kalaw Jr., Marvic F. Leonen, Luna ,Maria Paz G, and Jim J. Paredes. Lecture-Series on the Philippine Environment in the 21st Century: Issues and Concerns. Diliman, Q.C: UP Law Center, Institute of International Legal Studies, 1993.

Emmanuel, Jorge A., et al. Lecture-Series on the Philippine Environment in the 21st Century: Issues and Concerns. UP Law Center, Institute of International Legal Studies, 1993.