1. Who immunization data portal [internet]. World Health Organization. Available from: https://www.who.int/topics/immunization/en. [Last accessed on 09 Aug 2020]
2. Park K. Park’s textbook of preventive and social medicine. 25th ed. India: M/s Banarsidas Bhanot Publishers; 2019.
3. International Institute for Population Sciences (IIPS). National Family Health survey. Mumbai: IIPS. 1992-93; 1995. Available from: https://www.worldcat.org/title/national-family-health-survey-mch-and-family-planning-1992-93/oclc/33196470. [Last accessed on 09 Aug 2020]
4. International Institute for Population Sciences (IIPS), ORC Macro. National Family Health Survey. NFHS-2. India, Mumbai: IIPS; 2000. p. 1998-99. Available from: https://openlibrary.org/books/OL22461343M/National_family_health_survey_%28NFHS-2%29_1998-99. [Last accessed on 09 Aug 2020]
5. International Institute for Population Sciences (IIPS) and macro international. Mumbai: National Family Health survey NFHS-3, 2005-06: India. IIPS; 2007. Available from: https://dhsprogram/pubs/pdf/frind3/frind3-vol1andvol2.pdf. [Last accessed on 09 Aug 2020]