Polarizing Filters Are Essential — Unless They Aren't
The Physics of Polarizing Filters
How do polarized sunglasses work relative to polarizing filters for camera lenses? If you wear polarized sunglasses, is there an SLR camera filter that would give you a similar effect? - Quora
The Physics of Polarizing Filters
Linear Polarizer Film LCD/LED Polarized Filter Polarizing Film Sheet for PolarK5 | eBay
Simple demo shows the power of a polarizing filter: Digital Photography Review