1. Cepi, 2018. Paper and board production stable and market pulp production up in 2018 compared to 2017, accessed on July 25, 2018. Available from http://www.cepi.org/publication/preliminary-statistics-2017.
2. Viện công nghiệp giấy và xenluylô, 2017. Một số thống kê ngành bao bì giấy năm 2017, accessed on July 25, 2018. Available from http://rippi.com.vn/bvct/chi-tiet/80/-mot-so-thong-ke-nganh-bao-bi-giay-nam-2017.html.
3. Martin Yale, 2018. Paper folders, accessed on June 25, 2018. Available from https://martinyale.com/paper-handling-products/1217a-automatic-paper-folding-machine/.
4. PaperFolder, 2018. Folding Machines & Paper Folders, accessed on June 25, 2018. Available from https://www.paperfolder.com/Folding-Machines-and-Paper-Folders.html.
5. Raw T. S., 1966. Geometric Exercises in Paper Folding. Dover Publications, 31st ed., 148 pages.