"further stating" is correct and can be used in written English.
It is often used to add additional information or clarification to a previous statement. Example: John has been working on his project for weeks, and it is now almost complete. Further stating, he has put in numerous hours and it is evident in the quality of his work.
The IPCC went even further, stating that climate change impacts are projected "to prolong existing and create new poverty traps".
But lately, Mr. Greenspan has gone even further, stating that technology is driving the economy into a transformation so fundamental that there is nothing to compare it to.
The final climate amendment, introduced by the Hawaii Democrat Brian Schatz, went further, stating: "human activity significantly contributes to climate change".
Swedish newsagents went even further stating that Sweden's all-time-low PISA scores are a "national disaster" that puts the future of the nation at risk.
When the hearing was convened, she went a step further, stating that as a matter of principle she could not take part in the proceedings.
And a Jewish religious court in Crown Heights, Brooklyn, went further, stating that oral suction was a mandatory part of the procedure that should be promoted.
GK Chesterton went further, stating that "Dr Jekyll and Mr Hyde", though "presented as happening in London", was "very unmistakably happening in Edinburgh" - which is plausible, but unmistakably not the case.
Richard Reeves, managing director of the Association of Online Publishing goes one step further, stating that while Adblock Plus' move was inevitable, it "doesn't make it any less hypocritical or applaudable.
Just to clear up any ambiguities, Fox's Andrea Tantaros went one step further, stating: "If anyone sees this movie, which they should go see it, and then goes on to vote for Hillary Clinton, they're a criminal".
Another columnist, Timofei Sergeitsev, went further, stating that the "disgusting" American meddling in football was meant to "take the 2018 World Cup away from Russia and demonstratively bring the last independent organisation in the world under its control".
In 2011, the Marine Corps commandant signed an energy strategy that seeks to go even further, stating that by 2025 Marines will be 50percentt more fuel efficient on the battlefield.
