Stray comma after title of anonymous book

I am consistently getting a comma after the title of a book with no author, i.e., an anonymous book.  Can someone suggest a way to fix this?

The citation ends up looking like this:  

Gun Control Laws in Foreign Countries,  (Washington, D. C.: Library of Congress, Law Library, 1981)


Guide to the Manuscript Collections of Friends Historical Library of Swarthmore College,  (Swarthmore, Pa., 1982)

Which output style?  I suspect the Author and trailing comma need to be isolated between two pipe characters in the template for book, to associate the comma with the field.

Also there are fancy handling options by APA criteria which may help (in anonymous settings of the output style).  

The style is “J Amer Hist.ens”

I forgot to say that I just want to get rid of the comma.

Okay, I played with it and not sure what I did right, but see if this works now to expectations.  Check both an authors and anonymous book, and you may want to check long and short forms of the footnote and the Bibliography version, which I played with too.  

J Amer History (5.74 KB)