As far as possible, the information regarding formations is sourced from attendance at games backed by LUTV videos.

Unfortunately far too many websites and publications re-hash the predicted formations prior to kick-off rather than reporting on how the teams actually lined up.  However I do recommend The Football League Paper who make a bit more of an effort in this regard on their match report pages.

​Meanwhile the WhoScored? website has a phenomenal array of detailed statistics for every Championship game.  Their average player position charts are particularly useful for confirming the true formations deployed. 

A website I use heavily to help compile the teamsheets and moreover, to ensure a consistent approach to player naming is footballsquads.com.  This really is a fantastic resource and I am very grateful that the site owners make their work available for non-commercial use subject to the following acknowledgement:

Source of Material is http://www.footballsquads.com. Material: © FootballSquads.com, 1999 - 2019, All Rights Reserved

The kit graphics are my own and are kept deliberately generic but more detailed depictions can be found at the wonderful Historical Football Kits and Colours Of Football websites.

OTHER RECOMMENDED LINKS  

General
The League Paper
Football-Lineups
BBC Football
Sky Sports
Alt Om Fotball
Historical Lineups

Other clubs
Chelsea: Bounder Friardale
Liverpool: LFCHistory
Manchester City: Bluemoon
Sunderland: TheStatCat
Swindon Town: Swindon-Town-FC

Leeds
Leeds United Programme Guide
Leeds United Match Worn
Sheridan Dictates
Ozwhitelufc
Yorkshire Evening Post
WAFLL
Mighty Leeds
WACCOE forum
Leeds United Mad
Travels of a Leeds fan
Follow Me and Leeds United
Life, Leeds United, the Universe & Everything
David Watkins' Leeds United blog
Jabba's Leeds United Site (discontinued)

Twitter
@LUFCHistory
@lufcstats
@MrMacca1992
@super_leeds70
@andylimb

YouTube
lufc films
WALMOT
Leeds United History
Just Leeds - steakandsid