Rita Erlinda, et al. “Analysis of Factors Affecting Coffee Plantation Business Production in Bukik Barisan, Lima Puluh Kota”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 71, no. 1, Dec. 2023, pp. 181-6, https://www.gssrr.org/JournalOfBasicAndApplied/article/view/16405.