I'm not quite sure your Q has been answered.
You said: "If referencing the title of..."
So we're talking about scientific citation, right?
And this is about the US, is it not?
The American Anthropoligical Association says:
"Ligatures: Do not use except in an Old English language piece"
https://www.uvm.edu/wid/writingcenter/tutortips/AAAStyleGuid...The American Historical Review, the official publication of the American Historical Association, states:
"The footnote style used by the AHR generally follows the conventions recommended by The Chicago Manual of Style."
http://deerfield.history.museum/dtc/programs/American Histor...As per the Chicago Manual of Style (can't give a better link because you need to be logged in):
"When to use ligatures The ligatures æ ( a + e ) and...œ ( o + e ) should not be used in Latin or transliterated Greek words."
https://www.chicagomanualofstyle.org/search.epl?q=e book&sit...The Manual of Scientific Style (US publication) by Harold Rabinowitz and Suzanne Vogel: Don't use them except for Old English and French.
Best wishes