this link was posted earlier this year, could help with publisher digs:
https://almossawi.com/big-five-publishers/
(sorry, didnt know how to get that whole graphic into one screencap)
From back in September…
Trump recommends congressional investigations into Obama family book and Netflix deals
President Trump advised Congress to stop investigations into his businesses and focus on investigating the Obamas' book and Netflix deals.
"House Judiciary has given up on the Mueller Report, sadly for them after two years and $40,000,000 spent - ZERO COLLUSION, ZERO OBSTRUCTION. So they say, OK, lets look at everything else, and all of the deals that 'Trump' has done over his lifetime. But it doesn’t work that way," Trump said Monday morning on Twitter. "I have a better idea. Look at the Obama Book Deal, or the ridiculous Netflix deal. Then look at all the deals made by the Dems in Congress, the 'Congressional Slush Fund,' and lastly the IG Reports. Take a look at them. Those investigations would be over FAST!" 

….work that way. I have a better idea. Look at the Obama Book Deal, or the ridiculous Netflix deal. Then look at all the deals made by the Dems in Congress, the “Congressional Slush Fund,” and lastly the IG Reports. Take a look at them. Those investigations would be over FAST!
— Donald J. Trump (@realDonaldTrump) September 16, 2019
Since taking over the majority, House Democrats have started multiple investigations into Trump's businesses and personal finances. The president has tried to thwart the inquiries by stonewalling subpoenas.
In 2017, Barack and Michelle Obama signed a joint book deal worth a reported $65 million. They also inked a deal with Netflix in 2018 to produce content for the streaming company. Last month, the Obamas' first produced documentary, American Factory, streamed on Netflix.
Trump, 73, called for subpoenas of the book deal in July to counteract Democratic investigations into his businesses.
https://www.washingtonexaminer.com/news/trump-recommends-congressional-investigations-into-obama-family-book-and-netflix-deals
…and here…
“They could look into the book deal that President Obama made. Let’s subpoena all of his records,” Trump added in a video clip gleefully shared by Turning Point USA official Benny Johnson. “Let’s subpoena all of the records having to do with Hillary Clinton and all of the nonsense that went on with Clinton and her foundation and everything else.”
https://www.theepochtimes.com/trump-calls-for-probes-into-obama-book-deal-clinton-nonsense_3019255.html