Rohmer, Richard H
Chronological Checklist
Series – Robert Porter
- Ultimatum (Toronto, Ontario: Clarke, Irwin, 1973)
- Ultimatum: Oil or War (New York: Pocket Books, 1974)
- Exxoneration (Toronto, Ontario: McClelland and Stewart, 1974)
- Ultimatum 2 (Toronto, Ontario: Dundurn Press, 2007)