If you're talking about the latest game in the series, Sudden Strike 4, it's developed by KiteGames and published by Kalypso Media. However, you can't download or buy the game from there, as Sudden Strike 4 is being sold through the Steam platform.
In case you want one of the older games from the franchise, I don't think that you can download them from the official website anymore, so you might as well use the links that Software Informer provided to download them.