Corrections needed

I am looking for a good link with advice on making presentations for my students who are learning English. This looks like a good site but you need to make a few corrections before I can use it as a link. On [url]http://www.presentationhelper.co.uk/Essential_presentation_sklils_1_using%20visuals.ht m[/url] you say text represents 55% of the information retained and only 7% is text.

Then towards the bottom of the page there is a repetition of 'is'. The effect of using visuals is is truly staggering.

At the very bottom there is a repetion of the word link.

Since I am expecting pre-intermediate to intermediate level students this sort of error is just confusing.