The assertion that Earth's gravitational pull vastly exceeds the negligible tidal forces exerted by other planets on the human body is a straightforward consequence of the inverse-square law and basic Newtonian physics, requiring no citation.
The claim follows directly from the fundamental physics of gravity (Newton's law of universal gravitation), where the gravitational force depends on mass and the inverse square of the distance. Because astronomical bodies are either too small or too distant, their tidal forces on a human are demonstrably several orders of magnitude smaller than Earth's local gravitational pull. This is a matter of elementary physical calculation and everyday observation of physical laws, qualifying as common knowledge.