Gaya APA

Soemartono, ., al, E. (1991). Stratification of health centre (a case study) . Surabaya: Puslitbang Yantekkes, Badan Litbangkes.

Gaya MLA

Soemartono, ., al, Et. "Stratification of health centre (a case study)". Surabaya: Puslitbang Yantekkes, Badan Litbangkes, 1991. print.