Deletion of Duke Carl Gregor of Mecklenburg

Comment: I've added his reviewed books to the article along with more career details, have been clearer about the "former" part of his former-noble-title last name and cut  detail about his family, and have expanded sourcing.  If this ends in a keep, the article should be moved to "Carl Gregor Herzog zu Mecklenburg", as the name he operated under (including in contemporaneous English language reviews).  {{ping|David Eppstein}} do you still have serious remaining TNT concerns
Stance: comment
Cited policy: Wikipedia:Neutral point of view (WP:UNDUE)

Comment: Passes  as a member of high European nobility and rof as a jazz musicologist
Stance: keep
Cited policy: Wikipedia:Notability (WP:GNG||WP:P)

Comment: per , multiple independent reviews of multiple works.  Reviews of his books include https://www.jstor.org/stable/41116168https://www.jstor.org/stable/850529https://www.jstor.org/stable/41115482https://www.jstor.org/stable/23230661https://www.jstor.org/stable/23892876https://www.jstor.org/stable/896076https://www.jstor.org/stable/41116958.  Slightly weak only because some of the reviews are a fair ways towards the brief side
Stance: keep
Cited policy: Wikipedia:Notability (WP:NAUTHOR)

Comment: his academic background probably satisfies  
Stance: comment
Cited policy: Wikipedia:Notability (WP:NACADEMIC)

Comment: per  and 
Stance: keep
Cited policy: Wikipedia:The Heymann Standard (WP:HEY||WP:AUTHOR)