Please check the Book Title field in the Blackman reference for a blank line in the field.
If the reference does not have a blank line currently then I would suggest inserting Blackman into a new document to check how EndNote is formatting the reference.
If a new document is working properly then make a backup of your document and try the following steps from our website.
If the steps do not resolve the issue then please contact Technical Support directly
1-800-336-4474 option 4 then 1
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