It's strange to note that a Dirty Martini, probably one of the most popular cocktails in the world, isn't on the IBA list. Likewise I've found many cocktail books also won't deign to list it as a 'real' cocktail. But I'd argue the heritage is the same as a great many now classic prohibition drinks -- adding ingredients to distract from low quality liquors.

I think that's a disservice, and it's worth standardizing; just like many of these, it can be surprisingly hard to get just right.

Do yourself a favor and use cerignola olives.