  Verifiability is one of the core editing principles in Wikipedia, where
editors are encouraged to provide citations for the added statements.
Statements can be any arbitrary piece of text, ranging from a sentence up to a
paragraph. However, in many cases, citations are either outdated, missing, or
link to non-existing references (e.g. dead URL, moved content etc.). In total,
20\% of the cases such citations refer to news articles and represent the
second most cited source. Even in cases where citations are provided, there are
no explicit indicators for the span of a citation for a given piece of text. In
addition to issues related with the verifiability principle, many Wikipedia
entity pages are incomplete, with relevant information that is already
available in online news sources missing. Even for the already existing
citations, there is often a delay between the news publication time and the
reference time.
  In this thesis, we address the aforementioned issues and propose automated
approaches that enforce the verifiability principle in Wikipedia, and suggest
relevant and missing news references for further enriching Wikipedia entity
pages.
