एपीए उद्धरण

(2011). Water and air quality directory 2011. Kerala state pollution control board.

शिकागो स्टाइल उद्धरण

Water and Air Quality Directory 2011. Thiruvananthapuram: Kerala state pollution control board, 2011.

एमएलए उद्धरण

Water and Air Quality Directory 2011. Kerala state pollution control board, 2011.