  Modern software development methodologies include reuse of open source code.
Reuse can be facilitated by architectural knowledge of the software, not
necessarily provided in the documentation of open source software. The effort
required to comprehend the system's source code and discover its architecture
can be considered a major drawback in reuse. In a recent study we examined the
correlations between design metrics and classes' architecture layer. In this
paper, we apply our methodology in more open source projects to verify the
applicability of our method. Keywords: system understanding; program
comprehension; object-oriented; reuse; architecture layer; design metrics;
