Referencing a board game rule book I'm writing a paper on a board game, 
Labyrinth, and I need to use some parts of the rule book. How should I reference this? I'm using Harvard reference style.

EDIT: I hadn't notice this earlier.

What can be found in the start of the rule book is this:


  Author: Max J. Kobbert


And in the end, this:


  © 2007 Ravensburger Spieleverlag


EDIT 2: I found a link to the rule book. The real one contains for several more languages but the content is the same.

Link to rule book
The point of referencing is to allow others to determine what you've referenced and to look it up in turn. 

Harvard has tools for citing multi-media formats, such as board games. 

Inline: ([Rulebook] 1986). 

Biblio: [Rulebook] 1986 Labyrinth (boardgame), Ravensburger. 

Consult a full style guide and model off the nearest multi media work, for example, album liners to a CD.

Are you sure 2007 is really the date of the edition and not the printing?

(Kobbert 2007).

Kobbert, MJ 2007 '[Rulebook]' Labyrinth (boardgame), Ravensburger Spieleverlag.