Original sentence: However, recently this view has been questioned by the IPCC.The 2001 IPCC report says: "…current evidence does not support globally synchronous periods of anomalous cold or warmth over this timeframe, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries
Edited sentence: However, recently this view has been questioned (Bradley and Jones, 1993; Hughes and Diaz, 1994; Crowley and Lowery, 2000).The 2001 IPCC report summarises this research, saying: "…current evidence does not support globally synchronous periods of anomalous cold or warmth over this timeframe, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries