D'Andrea, W.J., Vaillencourt, D.A., Balascio, N.L., Werner, A., Roof, S.R., Retelle, M. and Bradley, R.S. 2012. Mild Little Ice Age and unprecedented recent warmth in an 1800 year lake sediment record from Svalbard. Geology 40: 1007-1010.
Working with "a sub-decadal- to multidecadal-scale record of summer temperature for the past 1800 years from lake sediments of Kongressvatnet on West Spitsbergen, Svalbard [78.016667° N, 13.983333°E] based on the first instrumental calibration of the alkenone paleothermometer," D'Andrea et al. determined that two episodes of relative summer warmth during the MWP (A.D. 1010-1060 and A.D. 1160-1250) were "2°C and 2.5°C colder, respectively, than mean JJA temperature from A.D. 1987-2009."