VIDYA PRAKASHAN. (2012). ENVIRONMENTAL STUDIES - BOOK 2. VIDYA PRAKASHAN MANDIR.
Cita Chicago (17th ed.)VIDYA PRAKASHAN. ENVIRONMENTAL STUDIES - BOOK 2. VIDYA PRAKASHAN MANDIR, 2012.
Cita MLA (9th ed.)VIDYA PRAKASHAN. ENVIRONMENTAL STUDIES - BOOK 2. VIDYA PRAKASHAN MANDIR, 2012.
Atenció: Aquestes cites poden no estar 100% correctes.