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.