Rahmat Syarif, Violita Violita, Irma Leilani Eka Putri, and Dezi Handayani, “The Effect of Use Ground Coffee (Coffea arabica L.) as a addition Nutrition To The Growth of Spinach Plants (Amaranthus hybridus L.) In Hydroponics Systems”, prosemnasbio, vol. 1, no. 2, pp. 1440–1449, May 2022.