Hasibuan, R. S., R. Soekmadi, H. Purnomo, and N. B. Mulyono. “Carbon Footprint Analysis and Tourist Satisfaction of 4As at an Ex-Situ Conservation Institution”. Jurnal Sylva Lestari, vol. 13, no. 2, May 2025, pp. 441-53, doi:10.23960/jsl.v13i2.1093.