Copyright © The Author(s) 2018. Published by Baishideng Publishing Group Inc. Articles published by this Open-Access journal are distributed under the terms of the Creative Commons Attribution Noncommercial License.
Except where otherwise noted, this item's license is described as Copyright © The Author(s) 2018. Published by Baishideng Publishing Group Inc. Articles published by this Open-Access journal are distributed under the terms of the Creative Commons Attribution Noncommercial License.