Another Ghostwriter found

[Bigfootman]

Not sure if anybody else has found this, but I was searching for Hardy Boys on google, when I discovered this interesting "about the author" section on amazon.

https://www.amazon.ca/Adolescence-Ian-McMahan/dp/0205843719
"Ian McMahan graduated from Princeton and received the Ph.D. in developmental psychology from the City University Graduate School. His doctoral dissertation won the James McKeen Cattell Prize, and his research papers have appeared in prestigious journals. Ian has also had an active writing career. His books include a novel, Footwork; the Microkid Mysteries for children; Get It Done!; Secrets of the Pharaohs; and many volumes in the Nancy Drew and Hardy Boys series of mysteries."

He also wrote an article in the October 1994 issue of Dime Novel Roundup about the Hardy Boys. ("Today's Hardy Boys Adventures: A Social Development Analysis.") Unfortunately, I've been unable to find any information about which Hardy Boys books he wrote.

[tomswift2002]

He's been writing books since 1963, so since all the Grosset & Dunlap authors are know, McMahan probably wrote some of the Wanderer/Minstrel/Aladdin/Archway books.

[Bigfootman]

I just found this.
https://www.amazon.com/Paul-Mantell/e/B001IO9UCQ
"Paul Mantell is the author or co-author of over 160 books for children and young adults. Hit series include Nancy Drew, Hardy Boys, Bobbsey Twins, Tom Swift, X-Men, Matt Christopher Books, Tiki and Ronde Barber Books, and Derek Jeter Books (he is currently working on Book #5 in that best-selling series). Paul lives in New Jersey with his wife (and erstwhile co-author) Avery Hart."
Once again, no info on which Hardy Boys books he wrote, although, it's highly likely (judging from the books he's written) that some of them were about sports. Although, interestingly enough, searching ""paul mantell" nancy drew" on Google lead to the amazon page for the GD book "Murder on the Set".