Haubrich, Hans-Jürgen;Dieter Denzel.«Characteristics of interconnected operation». A: Operation of Interconnected Power Systems(pdf).Aquisgrà:Institute for Electrical Equipment and Power Plants (IAEW) at RWTH Aachen University,2008-10-23,p.3[Consulta: 6 desembre 2008].Arxivat 2011-07-19 a Wayback Machine.(See "Operation of Power Systems" link for title page and table of contents.)
Haubrich, Hans-Jürgen;Dieter Denzel.«Characteristics of interconnected operation». A: Operation of Interconnected Power Systems(pdf).Aquisgrà:Institute for Electrical Equipment and Power Plants (IAEW) at RWTH Aachen University,2008-10-23,p.3[Consulta: 6 desembre 2008].Arxivat 2011-07-19 a Wayback Machine.(See "Operation of Power Systems" link for title page and table of contents.)