(原始内容存档于2016-01-06). David Ward. A Mapping Study ofMediaConcentration and Ownership in Ten European Countries (PDF). Dutch Media Authority. 2004 [2014-12-12]. (原始内容存档
(原始内容存档于2013-12-22). 出版社列表(英语:List of publishers) 媒體股權集中(英语:Concentrationofmediaownership) 精神藥理學 Press release on the merger of Springer and Kluwer (页面存档备份,存于互联网档案馆)
[2014-12-03]. David Ward. A Mapping Study ofMediaConcentration and Ownership in Ten European Countries (PDF). Dutch Media Authority. 2004 [2015-02-11]. (原始内容存档
(西班牙语). David Ward. A Mapping Study ofMediaConcentration and Ownership in Ten European Countries (PDF). Dutch Media Authority. 2004 [2014-02-19]. (原始内容存档