Dave Stein (Author: How Winners Sell) has written at length about the scurge of copyright abuse in the Sales Training business.
It can be difficult to determine exactly what's original and what isn't. Many different melodies can be composed from the three same chords.
As one prominent US sales trainer jokes on YouTube "I get my material from many sources. If it's just one source it's plagiarism, if it's from several, it's research"
Here is the same sales trainer along side David Sandler (recorded nearly two decades ago). Have a listen, first to David Sandler, then to the other trainer. Is is just the words or is the melody the same?
The three qualifying steps of the Sandler Selling System;
The three qualifying steps of this trainers selling system;
A coincidence - perhaps. You be the judge...
Plagiarism or research?