[1] hOCR - OCR Workflow and Output embedded in HTML (2017-04-24 16:36:54 +09:00) <https://kba.github.io/hocr-spec/1.2/>

[2] hocr-spec/spec.md at master · kba/hocr-spec (2017-07-09 00:12:10 +09:00) <https://github.com/kba/hocr-spec/blob/master/1.1/spec.md>

[3] kba/hocr-spec: The hOCR Embedded OCR Workflow and Output Format (2017-07-09 00:13:13 +09:00) <https://github.com/kba/hocr-spec>

[4] hOCR - Wikipedia (2017-06-24 02:35:26 +09:00) <https://en.wikipedia.org/wiki/HOCR>