एपीए उद्धरण

(2012). Water and air quality directory 2012. Kerala Pollution Control Board.

शिकागो स्टाइल उद्धरण

Water and Air Quality Directory 2012. Kerala Pollution Control Board, 2012.

एमएलए उद्धरण

Water and Air Quality Directory 2012. Kerala Pollution Control Board, 2012.