Marriage certificate obtained overseas

My wife and I got married in USA and have a certificate of marriage certified and approved by the state of Nevada. My wife is a Shanghainese and I'm a Singaporean. Before getting the certificate if marriage, we have already completed the notorization in USA.

Now that we are back in China and we would like to get a certification from the Chinese Government for our marriage certificate obtained in USA. What do we have to do?

The reason for the Chinese certification is in respect to the work benefit according to the labour law of China.