Gaya APA

Hutagalung, M, S. (2009). Gemstones of life: poems of the elderly = Permata kehidupan : sajak-sajak lansia . io: .

Gaya MLA

Hutagalung, M., S.,. "Gemstones of life: poems of the elderly = Permata kehidupan : sajak-sajak lansia". io: , 2009. print.