Citazione APA

Radha, S., & Sankhyan, A. S. (2002). Environmental challenges of the 21st century. Deep & Deep.

Stile di citazione Chicago

Radha, S., e Amar Singh Sankhyan. Environmental Challenges of the 21st Century. New Delhi: Deep & Deep, 2002.

Citazione MLA

Radha, S., e Amar Singh Sankhyan. Environmental Challenges of the 21st Century. Deep & Deep, 2002.