The webapp provides for each item the link on ECB's website.
Speeches for : Yves Mersch where "definition" appeared
2020-09-23 : Interview with Bloomberg2019-02-04 : The changing role of central banking
2018-09-06 : Financial stability and the ECB
2016-10-03 : The challenge of low interest rates for banks within the banking union
2013-06-13 : Monetary policy in an environment of low growth and interest rates