Pedro Martínez: Those rules in your link are not very well written and have the feel of someone translating them from a different language. I know what playBunny means by official rules. Baseball has such a set of them. Table of contents and the various aspects of the game broken down into chapters and subsections. I've always wanted to find such a rule book for NFL rules, but have not been able too. I'm sure there's a place for Backgammon rules on the internet. I have a copy of the "Official Rules of Backgammon" in a book written by Oswald Jacoby and John R. Crawford and published in 1970. The two paragraphs before the actuals rules are:

As we said in the Introduction, back in 1931 Wheaton Vaughan, the chairman of the Card and Backgammon Committee of the Racquet and Tennis Club of New York, invited representatives of the other clubs to join with the Racquet Club in order to produce a code of laws for Backgammon. That code was soon universally adopted and accepted generally. As far as we know, Oswald Jacoby is the only member of the committeee still alive, but their laws have lasted with practically no change, and the laws presented here are essentially the same. They have been prepared in conjunction with the International Backgammon Association and the Inter-Club League of New York.
Remember that laws are made to prevent arguments, not to cause them. Never attempt to use the laws to gain an advantage.

Then it lists 34 laws of Backgammon.
1 through 6 define the game
7 through 10 define the throwing of the dice and when a player's turn ends
11 though 17 define the play and how the dice are used
18 and 19 deal with errors, in the set up or playing
20, 21, and 22 deal with scoring the game after it ends
23 through 34 deal with Chouette, which is backgammon for three or more people.

The next chapter in this book has modifications to these rules rules some people might want to play with or can be used in tournament play.

In all this I find it amazing how simple a game Backgammon is and yet how complicated the play of it can be. Good qualities in any game.

I have a saying about games, "If you can't argue about it, it usually ain't much fun to play."

playBunny: Maybe you can use some of the keywords in the paragraph in a google search and find some links that way. Since my book is over 30 years old, some of the organizations might have merged into others or gone out of business. The authors should be a good link. Rex Nihilo mentions a Walter Trice as a good source of modern Backgammon information. Try asking him if knows about a rule book or link. He gave me a link for a book store that carries Backgammon stuff. I'm sure he could help you out.