Arctic Sea Ice News & Analysis – April 2008 [2]Arkivigite je 2020-12-08 per la retarkivo Wayback Machine Alirita la 22an de Aprilo 2017.
uiuc.edu
arctic.atmos.uiuc.edu
Polar Sea Ice Cap and Snow – Cryosphere Today, University of Illinois [1]Arkivigite je 2011-02-23 per la retarkivo Wayback Machine Alirita la 22an de Aprilo 2017.
web.archive.org
Polar Sea Ice Cap and Snow – Cryosphere Today, University of Illinois [1]Arkivigite je 2011-02-23 per la retarkivo Wayback Machine Alirita la 22an de Aprilo 2017.
Arctic Sea Ice News & Analysis – April 2008 [2]Arkivigite je 2020-12-08 per la retarkivo Wayback Machine Alirita la 22an de Aprilo 2017.