Gaya APA

Purba, O, D. (2019). Daily Routines to be a Happy Person (Cet. 1). Yogyakarta: Laksana.

Gaya MLA

Purba, Olivia, Dianina. "Daily Routines to be a Happy Person". Cet. 1 Yogyakarta: Laksana, 2019. Text.