Working Permit for married couple? (Istanbul)

Hi everyone,

I was recently told that if you are married and your spouse is already working in Turkey as an expat, for a company that has a legal entity in Turkey (which is the case for most International companies), you are not allowed to work in Turkey yourself.

Does anybody have any information about this? Is there a good 'official' website (in English), where this type of information can be verified?

Thanks in advance :)