From general articles to detailed ones, the following are some useful sites, studies and articles.
Some are behind pay-walls, but will allow you a certain number of free reads.
The article that made me retrain
A light article but an interesting read
BBC article on sleep in general. An interesting read
Vogue wakes up to CBT-I in 2017. Pardon the pun
A useful article on commonly held beliefs
Introductions to CBT-I
An introduction to CBT-I
Guardian article on CBT-I from July 2019
An endorsement for CBT-I by the American College of Physicians
Doing it yourself and apps
The pros and cons of a do-it-yourself approach
..especially if you think about it too much
Interesting reading on sleep apps
A more up-to-date article on sleep apps
Another from June 2019
Say goodbye to those weekends in bed..
Article about Wales’ (UK) insomnia problems
Telephone-delivered CBT-I for menopausal women
An in-depth look at CBT-I and related studies