According to Hübner-Bloder et al., 2005, the domain
layer describes a hospital independently of its
implementation by its enterprise functions. The logical
tool layer shows the application components. Application
components support enterprise or hospital functions
and ‘are responsible for processing, storage and
transportation of data. On the physical tool layer there ‘is
a set of physical data processing components‘ that
are ‘used to realize the computer-based and the
paper-based application components‘