APA Format
WHO ( world health Organization ) . (). Bugs,...: Smallpox eradicating an ancient scourge. ( Ket. Lihat halaman 1-21 ) ( Bab. 1 ) . : World Health Organization, 2012
MLA Format
WHO ( world health Organization ) . Bugs,...: Smallpox eradicating an ancient scourge. ( Ket. Lihat halaman 1-21 ) ( Bab. 1 ) . : World Health Organization, 2012,
Australian/Harvard Format
WHO ( world health Organization ) . . Bugs,...: Smallpox eradicating an ancient scourge. ( Ket. Lihat halaman 1-21 ) ( Bab. 1 ) . World Health Organization, 2012, 
Warning: These citations may not always be 100% accurate.