In it the heads of state pledge to "continue consolidated actions to counter Russia's aggression in Ukraine."
"If we allow such fundamental violations of international law to go unpunished, we will suffer from the instability that will follow," Obama and Cameron note.
"We have sent an unequivocal signal: the international community will not support Russia's efforts to destabilize Ukraine," Obama stated.
The joint article was published on the eve of Cameron's visit to the U.S., where he and Obama will also discuss the issue of cybersecurity.
Among other things, Cameron boasted informal relations in dealing with Obama - according to the Prime Minister, the U.S. leader often calls him "bro".