Please help! Book name

[Christie Gahan]

Hi guys:  What is the classic / bible of mobile home investing?  I read a book like 15 years ago, and it was more then 15 years old then.  It went all in on the crazy math of owner finance on used mobiles.  I think it was the first time I heard the phrase, "mailbox money".   If this rings a bell with anybody I would love to know the title.  If you have no idea what I'm talking about, what is a good book?