Zhang, Q., Gemmer, M. and Chen, J. 2008. Climate changes and flood/drought risk in the Yangtze Delta, China, during the past millennium. Quaternary International 176-177: 62-69.
Based on a study of historical documents covering the period AD 1000-1950 and actual instrumental data from meteorological stations for the period 1950-2003, Zhang et al. developed a millennial-scale temperature index for the Yangtze Delta region of China that revealed "three distinct climate periods" - the "Warm Medieval Period (AD 1000-1400), Little Ice Age (AD 1400-1920), and the ongoing well-established Global Warming Period (AD 1920-present)." Based on this record, it can readily be determined there was a continuous period from about AD 1200 to 1235 when it was significantly warmer than the peak warmth recorded during the "well-established Global Warming Period."