Aylward R (2006). "Eradicating polio: today's challenges and tomorrow's legacy". Ann Trop Med Parasitol. 100 (5–6): 401–13. doi:10.1179/136485906X97354. PMID16899145.
Aylward R (2006). "Eradicating polio: today's challenges and tomorrow's legacy". Ann Trop Med Parasitol. 100 (5–6): 401–13. doi:10.1179/136485906X97354. PMID16899145.
McNeil, Donald (1 กุมภาพันธ์ 2011). "In Battle Against Polio, a Call for a Final Salvo". New York Times. สืบค้นเมื่อ 1 กุมภาพันธ์ 2011.; excerpt, "... getting rid of the last 1 percent has been like trying to squeeze Jell-O to death. As the vaccination fist closes in one country, the virus bursts out in another .... The [eradication] effort has now cost $9 billion, and each year consumes another $1 billion."