Yanto Jailani, H. ., N. Nofialdi, and Z. Zulvera. “Analysis of Factors Affecting Coffee Farmer Behavior in Tanah Datar District”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 48, no. 3, Oct. 2019, pp. 278-90, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/10353.