And OP, please brush up on your research skills. You also might want to drop out of any academic programme you are currently enrolled in. Prioritising an online discussion forum run by foreigners targeting a mostly foreign audience over a quick and simple search engine query indicates that you are either not passionate about research or illiterate in identifying the quality of sources. If you need to do your presentation for work, I’d say it’s even worse and you are entirely unqualified for whatever your responsibilities are.
(And to any mod reading my complaint: it did positively contribute to OP’s question, I should be entitled to an opinion)
Hisnhai, thanks for your honesty. The prior poster’s links were useful. Yours were not. So I did receive the help I asked for here, and you got to take out your frustrations, whatever their source, so we have all come out ahead.
I hope you are just having a bad day, and I hope you usually have better ones.