Randomness
Comprehensive reference on physically based rendering techniques
An introduction to Monte Carlo ray tracing
An overview various variance reduction techniques for Monte Carlo rendering, covering bidirectional path tracing, Metropolis-Hastings algorithm, MIS, stratified Sampling, low-discrepancy sampling, blue noise, photon mapping, and finite element radiosity
The classic Kajiya rendering equation paper introduced the "rendering equation" and the path tracing algorithm
A good introduction on the use of different types of noise for random number generation, focusing on applications in real time rendering
the Academy Award-winning Ph.D. thesis by Eric Veach. It starts from bidirectional light transport algorithms and introduces multiple importance sampling and Metropolis light transport
An overview of different sampling strategies used in ray tracing.
Classic paper introducing a fast and simple filter for ray tracing denoising.
An explanation of direct lighting and next event estimation in ray tracers
This paper analyze the hash functions to make recommendations on which hash functions offer the best quality/speed trade-off for the range of needs, from high-performance/low-quality to high-quality/low-performance. It also present a new class of hash tuned for multidimensional input and output that performs well at the high-quality end of this spectrum.
Article from the "blue noise guy" talking about how to apply blue noise to raytraced soft shadows
