Spherical Worlds was created in 1996.
Spherical Worlds happened in 1996.
Spherical Harmonic was created in 2001-12.
Still Life with Spherical Mirror was created in 1934.
When Worlds Collide was created in 1933.
Different Worlds was created in 1979.
Hunter of Worlds was created in 1977.
Wizards' Worlds was created in 1989.
Active Worlds was created in 1995.
Spindizzy Worlds was created in 1990.
Forgotten Worlds was created in 1988.
Frontier Worlds was created in 1999.
Worlds of the Imperium was created in 1962.