# Quiz FC data: sources, licence and attribution

## The data file is CC BY-SA 4.0

`pl-history.v2.json` (the Premier League history the games read) is
distributed under the **Creative Commons Attribution-ShareAlike 4.0
International** licence: <https://creativecommons.org/licenses/by-sa/4.0/>.

You may copy, share and adapt it, including commercially, provided you give
appropriate credit, link the licence, say what you changed, and release your
adaptation under the same licence. Quiz FC adds no further terms and no
technical restriction to the file. This licence covers the data file only,
not the Quiz FC application code that reads it.

## Sources

| Source | Licence | Used for |
|---|---|---|
| **Wikipedia** club-season articles and player infoboxes, by Wikipedia contributors | CC BY-SA 4.0 | Player league appearances and goals per club-season; career PL totals per club spell |
| **openfootball/england** (<https://github.com/openfootball/england>) | CC0 1.0 | Every match result, from which the clubs per season and the final tables are computed |
| **Wikidata** (<https://www.wikidata.org>) | CC0 1.0 | Player identity (QIDs), dates of birth, nationality, name variants, fame signal |

The CC0 sources need no attribution; they are credited as a courtesy.

## Changes made to the Wikipedia material

Football statistics adapted from Wikipedia articles by Wikipedia contributors,
CC BY-SA 4.0. Changes: extracted the league (Premier League) appearance and
goal columns from squad-statistics tables, league goals from match-result
"Scorers" columns, and senior-career spells from player infoboxes; checked
them against the CC0 results; merged them with Wikidata identity; and
re-encoded them as compact JSON. Cup and European figures were excluded.

## Every revision used

`attribution.json` (same folder) lists every Wikipedia page revision the
statistics were adapted from, each with:

- `title`: the article,
- `url`: a permanent link to the exact revision (`oldid`),
- `history`: the article's history page (its list of authors),
- `use`: what the page was used for ("club-season stats" or "career totals").

## Not used

No data from premierleague.com, the Fantasy Premier League API, Opta or any
other league-owned feed is included.