Free-air gravity anomaly atlas of the world

The warlord of Mars #3

Edgar Rice Burroughs

The Child's Book of Nature: for the use of families and schools : intended to aid mothers and ..

Worthington Hooker

Geodesy

U.S. Coast and Geodetic Survey.

Centrifugal force and gravitation

John Harris

The Collapsing Universe

Isaac Asimov

Gravity is a Mystery

Franklyn M. Branley

Force Makes Things Move

Kimberly Brubaker Bradley

Handbook of mass measurement

Jones, Frank E.

Mysteries of the Universe

Jim Whiting

Friction and gravity

Marcus Figorito