The webapp provides for each item the link on ECB's website.
Speeches for : Benoit Coure where "scarcity" appeared
2017-11-14 : Asset purchases, financial regulation and repo market activity2017-04-03 : Bond scarcity and the ECB's asset purchase programme
2015-03-10 : Embarking on public sector asset purchases
2012-10-01 : Collateral scarcity - a gone or a going concern?