  HeidelTime is one of the most widespread and successful tools for detecting
temporal expressions in texts. Since HeidelTime's pattern matching system is
based on regular expression, it can be extended in a convenient way. We present
such an extension for the German resources of HeidelTime: HeidelTime-EXT . The
extension has been brought about by means of observing false negatives within
real world texts and various time banks. The gain in coverage is 2.7% or 8.5%,
depending on the admitted degree of potential overgeneralization. We describe
the development of HeidelTime-EXT, its evaluation on text samples from various
genres, and share some linguistic observations. HeidelTime ext can be obtained
from https://github.com/texttechnologylab/heideltime.
