References: 
General Relativity - Wikipedia
https://en.wikipedia.org/wiki/General_relativity
Field Equations - Warwick Department of Physics
https://warwick.ac.uk/fac/sci/physics/intranet/pendulum/generalrelativity/
Heisenberg’s Uncertainty Principle - Wikipedia
https://en.wikipedia.org/wiki/Uncertainty_principle
Stress-Energy Tensor - Wikipedia
https://en.wikipedia.org/wiki/Stress%E2%80%93energy_tensor
Einstein’s Field Equations - Wikipedia
https://en.wikipedia.org/wiki/Einstein_field_equations
Einstein Tensor - Wikipedia
https://en.wikipedia.org/wiki/Einstein_tensor
Pseudo-Riemannian Manifold - Wikipedia
https://en.wikipedia.org/wiki/Pseudo-Riemannian_manifold
Metric Tensor - Wikipedia
https://en.wikipedia.org/wiki/Metric_tensor
Ricci Curvature - Wikipedia
https://en.wikipedia.org/wiki/Ricci_curvature
Metric Tensor in General Relativity - Wikipedia
https://en.wikipedia.org/wiki/Metric_tensor_(general_relativity)
Schwarzschild Metric - Wikipedia
https://en.wikipedia.org/wiki/Schwarzschild_metric
Einstein’s Theory of General Relativity - SPACE.com
https://www.space.com/17661-theory-general-relativity.html
Gravitational Lensing - Wikipedia
https://en.wikipedia.org/wiki/Gravitational_lens
Laser Interferometer Gravitational Wave Observatory - Wikipedia
https://en.wikipedia.org/wiki/LIGO
Equivalence Principle - Wikipedia
https://en.wikipedia.org/wiki/Equivalence_principle
Gravitational Time Dilation - Wikipedia
https://en.wikipedia.org/wiki/Gravitational_time_dilation