Gerald Kramer's sleaze novels

I wrote a little post about Gerald Kramer's sleaze novel published in Finnish the early seventies as Seksimotelli (= "Sex Motel"). The original title for the book is said to be Swap Motel. I can't find that book, but I found these books for Kramer from Abebooks:

The Dangerous Age. Midwood 1964. (A double with Joan Ellis: High School Hellion.)

The Wrong Kind. Midwood 1965. (A double with Amanda Moore: Never Ask Why.)

Penthouse Party. Midwood 1965.

Come Be My Slave. Midwood 1965.

Apartment Party. Midwood 1966. 

Miss Round Heels. Midwood 1968.

Fresh Tail. Midwood 1970.

Swap Motel. Midwood? Pre-1972.