Fred Leuchter
1988 - a death machine expert consultant for American prisons, takes a look at the "Auschwitz Gas Chambers". He was hired by a man on trial in Canada, one of many nations where one goes to prison for holocaust denial. After this report, Leuchter's work went away as a prison death machine expert and was required to become a telemarketer, the only option for such a criminal.
David Irving
David Irving is the most well know and proliferic writer as relates to WWII. He is an England citizen. See his books listing here: https://www.thriftbooks.com/a/david-irving/212630/ He is labeled as a holocaust denier, because he writes truth contrary to the 6 million itched in the minds of every person in the world. In most nations where white people live, it is a go to prison crime to deny the holocaust in public.
David Irving, article in the leftist Guardian, an English vehicle like leftist CNN, CBS, NBC, ABC except in print. https://www.theguardian.com/uk-news/2017/jan/15/david-irving-youtube-inspiring-holocaust-deniers
David Irving gets 3 years in jail for holocaust denial. - https://www.cbsnews.com/news/holocaust-denial-gets-3-years-in-jail/ https://www.reuters.com/article/us-austria-irving-idUSL2050544420061220/
The Holocaust as a Mechanism for Supressing the Truth, essay by Louis Beam
http://www.louisbeam.com/holocaust.htm
Tons of Data, From Researchers, Taking a 2nd Look at the 6 Million - on the Internet
Do a search.