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If you do not want them coming after you personally then you will need to incorporate or do an LLC. My suggestion is that you do an S corp and you can do this online without an attorney at the link below. An S corp will protect you from personal liability and will allow you tax savings so that you are taxed just like a partnership and not taxed twice like a C corp.
If you go this route, then you do not need to file an assumed name certificate if your corporate name is XXXXX XXXXX you plan to use for your business.
There are other links that offer the same service, just check it out on Google.