Jahns, Yvonne (Ed.) and IFLA Working Group on Guidelines for Subject Access by National Bibliographic Agencies. Guidelines for Subject Access in National Bibliographies. Berlin, Boston: De Gruyter Saur, 2012. Web. Retrieved 19 May. 2013, from http://www.degruyter.com/view/product/181808

Jahns, Y. (Ed.) & IFLA Working Group on Guidelines for Subject Access by National Bibliographic Agencies (2012). Guidelines for Subject Access in National Bibliographies. Berlin, Boston: De Gruyter Saur. Retrieved 19 May. 2013, from http://www.degruyter.com/view/product/181808

Jahns, Yvonne (Ed.) and IFLA Working Group on Guidelines for Subject Access by National Bibliographic Agencies. 2012. Guidelines for Subject Access in National Bibliographies. Berlin, Boston: De Gruyter Saur. Retrieved 19 May. 2013, from http://www.degruyter.com/view/product/181808