code: @Override
      public final Iterable<SourceDocument> findAll(
              final RootDocument rootDocument) {
          final Iterable<SourceDocument> sourceDocuments =
                  findAll(rootDocument.getFilename());
          if (sourceDocuments == null) {
              return null;
          }
          for (final SourceDocument sourceDocument : sourceDocuments) {
              final Source source = sourceDocument.getGedObject();
              source.setParent(rootDocument.getGedObject());
          }
          return sourceDocuments;
      }
docs: {@inheritDoc}