- StackOverflow post on converting Unicode
- StackOverflow post on converting XML to CSV
- StackOverflow post on checking a string for non-Latin characters
- StackOverflow AlKid's solution to the function finding numbers in strings
- SQLite documentation on importing CSV files
- ElementTree documentation
- Python CSV module documentation
- Wikipedia article on postal codes in Poland
- Online search engine for postal codes in Poland
- The excellent sample project, linked up in the course pages, was my constant source of inspiration