APA Format
USAID . (). Immunization essentials: a practical field guide. : Washington DC: USAID, 2003
MLA Format
USAID . Immunization essentials: a practical field guide. : Washington DC: USAID, 2003,
Australian/Harvard Format
USAID . . Immunization essentials: a practical field guide. Washington DC: USAID, 2003, 
Warning: These citations may not always be 100% accurate.