Summer temperature variations in Lapland during the Medieval Warm Period and the Little Ice Age relative to natural instability of thermohaline circulation on multi-decadal and multi-centennial scales. - Helama, Samuli; Timonen, Mauri; Holopainen, Jari; Ogurtsov, Maxim G.; Mielikäinen, Kari; Eronen, Matti; Lindholm, Markus; Meriläinen, Jouko (Journal of Quaternary Science, 2009)