New algorithms to improve the sensitivity of differential protection of regulating transformers. 2003. [PUMA: ATP-EMTP Differential Modeling Regulating Sensitivity Tap changer protection transformer] URL
A Dynamic Model of Transformer with Tap Changer Using BCTRAN-Routine and 94-Type. 23-31, 2005. [PUMA: BCTRAN-Routine Changer Norton Phase-shifting Regulating Tap Type-94 transformer] URL
Universal Adaptive Differential Protection for Regulating Transformers. IEEE Transactions on Power Delivery, (23)2:568-575, 2008. [PUMA: (EMTP) Differential Electromagnetic Program Tran-sients changer phase protection regulating shifters tap transformer] URL