The webapp provides for each item the link on ECB's website.
Speeches for : Lucas Papademos, Jean-Claude Trichet where "imbalance" appeared
2008-05-08 : Introductory statement with Q&A2006-05-04 : Introductory statement with Q&A
2006-04-06 : Introductory statement with Q&A
2006-01-12 : Introductory statement with Q&A