I’ve had a hard time finding a concise explanation of the rankings of poker hands that’s suitable for use as a reference by new players. In particular, the rules for comparing between hands of the same type (e.g. if two players have flushes, which one wins) are generally described in a very ad-hoc manner.
So I wrote them up myself, in Markdown (aka text) format. I converted this to HTML and added some simple styling to create a poker hand reference that fits on a single sheet of paper, and combined it with a quick-reference listing of hand types to make a PDF reference card—print it four sheets to an A4 page, double-sided, and you can cut it down to a four A6 references. All three of these are licensed under the Creative Commons by-nc-sa license.