About this article
Published Online: Dec 30, 2021
Page range: 155 - 164
Received: Jun 17, 2021
Accepted: Sep 24, 2021
DOI: https://doi.org/10.2478/amns.2021.2.00157
Keywords
© 2021 Chunguang Liu, published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.
Liu, Chunguang
Yantai Vocational CollegeYantai, China