1. ISO/IEC 18004:2015: Information Technology—Automatic Identification and Data Capture Techniques—QR Code Bar Code Symbology Specification
https://www.iso.org/cms/render/live/en/sites/isoorg/contents/data/standard/06/20/62021.html
2. Hexagonal, Information Encoding Article, Process and System
https://patents.google.com/patent/US4874936/en
3. Maxicode Data Extraction Using Spatial Domain Features
https://patents.google.com/patent/US5637849A/en
4. ISO/IEC 16023:2000: Information Technology—International Symbology Specification—MaxiCode
https://www.iso.org/cms/render/live/en/sites/isoorg/contents/data/standard/02/98/29835.html
5. ARToolKit: Library for Vision-based Augmented Reality;KATO;Tech. Rep. IEICE. PRMU,2002