H. Wibisana and A. Rumintang, Sehat di Usia Senja: Mengungkap Manfaat dan Risiko Kopi serta Teh. PT. Ghani Press Group, 2026. Accessed: May 02, 2026. [Online]. Available: https://e-book.ghanipress.com/index.php/ghanipress/catalog/book/42