- Series: Robert Allison Series Record # 43766
- Series Tags: antigravity (1), four dimensional surgery (1), four dimensional tools (1), hollow earth (1), inner earth sun (1)
- Robert Allison
- 1 Beyond Gravity (1929) [SF] by Ed Earl Repp
- 2 The Annihilator Comes (1930) [SF] by Ed Earl Repp