Norm Sperling
October 3, 1981: AstroAssembly
The Largest Meteor Crater in North America
October 4, 1980: AstroAssembly
Most Mysterious Talk at Astro Assembly
October 6, 1979: AstroAssembly
The Most Mysterious Manuscript in Astronomy
October 7, 1978: AstroAssembly
The Earth as Seen From Space
October 8, 1977: AstroAssembly
Unsafe at any Density
March 4, 1977: Monthly Meeting