NHL Data: https://www.naturalstattrick.com/teamtable.php
SHL Data: http://www.betterthanamonkey.com/?page_id=3344
Advanced statistics article (1): https://theathletic.com/121980/2017/10/09/an-advanced-stat-primer-understanding-basic-hockey-metrics/
Advanced statistics article (2): http://www.betterthanamonkey.com/?p=3249
Advanced statistics article (3): https://puckpedia.com/stats