If you're going to cite anything, cite the original letter, which was featured in a relatively high impact journal: http://www.mdpi.com/2072-6643/6/10/4472 http

If you're going to cite anything, cite the original letter, which was featured in a relatively high impact journal: http://www.mdpi.com/2072-6643/6/10/4472 http://www.mdpi.com/2072-6643/6/10/4472 I've not had time to review it yet.