What is PMF?
http://christophjanz.blogspot.com/2017/06/wtf-is-pmf-part-1-of-2.html
How to know if you've got a product market fit
https://www.lennyrachitsky.com/p/how-to-know-if-youve-got-productmarket
The Illusion of Product/Market Fit for SaaS Companies
https://feld.com/archives/2015/01/illusion-product-market-fit-saas-companies.html
Comment bien faire sa recherche utilisateur ?
https://medium.com/frstvc/réussir-ses-user-interviews-pour-réussir-sa-startup-6bad49ac975f
Use feedback to find product / market fit
https://review.firstround.com/how-superhuman-built-an-engine-to-find-product-market-fit