APA
Kumari R., . (2021). Environmental Challenges of the 21 Century. Chennai: Gyan geeta prakashan.
Chicago
Kumari Reena, . 2021. Environmental Challenges of the 21 Century. Chennai: Gyan geeta prakashan.
Harvard
Kumari R., . (2021). Environmental Challenges of the 21 Century. Chennai: Gyan geeta prakashan.
MLA
Kumari Reena, . Environmental Challenges of the 21 Century. Chennai: Gyan geeta prakashan. 2021.