Superanima,
Your formula is probably fine, but just be careful when using RegEx. Because of it's power and versatility, it is very easy to create a formula that
seems to do what you want.
The formula could also find some close, but not exact, matches. Unfortunately you only find out about these errors after the fact. Always try to match a unique combination of characters. If your program allows it also use manual search & replace, not automatic. This makes sure you do not accidentally make things harder for yourself. At least until you get a better understanding of RegEx.
Edit: I should mention that I've discovered this the hard way!