[edwin hubble]

"We're already fighting WWIV."

That model is as follows:

1914-1918 WWI
1939-1945 WWII
1945-1990 WWIII (Cold War)
2001- WWIV (War on Terror)

[docbnj]

We're already fighting WWIV."

That model is as follows:

1914-1918 WWI
1939-1945 WWII
1945-1990 WWIII (Cold War)
2001- WWIV (War on Terror)

Your chronology is correct.