What age to start E-collar?

A question here about collars. I have seen an artical about different collars. What someone has done was to test 100 dogs for each collar, choke, flat, and pinch. The study showed that the pinch collar was the collar that had the least amount of injuries to the dog.

I want to find that artical again so that I can direct people to it when they tell me how bad the pinch collar is.

Thanks

I found this one but it don't have the flat collars too.

A Study on Prong Collars was done in Germany:
100 dogs were in the study. 50 used choke and 50 used prong.
The dogs were studied for their entire lives. As dogs died, autopsies were performed.
Of the 50 which had chokes, 48 had injuries to the neck, trachea, or back. 2 of those were determined to be genetic. The other 46 were caused by trauma.
Of the 50 which had prongs, 2 had injuries in the neck area, 1 was determined to be genetic. 1 was caused by trauma.
The numbers seem to speak for themselves.
(Information about above study taken from an Anne Marie Silverton Seminar)