How can I download an older version "minecraft_server.jar" for Minecraft? [duplicate]

I am a YouTuber and I'm thinking of making a modded series with my friend. I went to the Minecraft website to download v1.6.4 of the server, but they don't have it. So I then searched via Google and found McNostalgia and MVC (Minecraft Version Changer) but it only had v1.6.2 and below.

How can I obtain the Minecraft server jar for an older version?

An extensive list of download links to older minecraft.jars and minecraft_server.jars can be found on https://mcversions.net/.

The links provided on that site are the same as the download links provided in Mojang's update posts, like this one, and hosted by Mojang themselves (Rehosting would violate Mojang's TOS).

In their own words:

[MCVersions.net] is a small project designed to make obtaining versions of Minecraft easy and simple. All content is provided by Mojang and is never re-distributed. [...] this website [is] not affiliated with Mojang AB.

You can download v.1.6.4 of “minecraft_server.jar” here:
https://s3.amazonaws.com/Minecraft.Download/versions/1.6.4/minecraft_server.1.6.4.jar