1. Apache Tika - a content analysis toolkit. https://tika.apache.org/
2. Apache Tika - Class PDFParser. http://tika.apache.org/1.24.1/api/org/apache/tika/parser/pdf/PDFParser
3. Bash Reference Manual. https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html
4. Coronavirus 10-day forecast. https://covid19forecast.science.unimelb.edu.au/
5. Cron(8)—linux manual page. https://man7.org/linux/man-pages/man8/cron.8.html