Hugo Estrada Oscar Pastor Alicia Martínez Jose Torres-Jimenez Using a Goal-Refinement Tree to Obtain and Refine Organizational Requirements. 506-513 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3046&spage=506 2004 conf/iccsa/2004-4 ICCSA (4) db/conf/iccsa/iccsa2004-4.html#EstradaPMT04