docs: function(next) {
              fs.readFile(path.join(config.root_out, config.akashacmsEPUB.bookmetadata.toc.href), 'utf8',
                  function(err, data) {
                      if (err) next(err);
                      else {
                          // logger.info('read '+ path.join(config.root_out, config.akashacmsEPUB.bookmetadata.toc.href));
                          tocHtml = data;
                          next();
                      }
                  });
          }