The phrase "a protocol was signed" is correct and usable in written English.
It can be used in contexts where an agreement or formal procedure has been officially accepted or enacted by the involved parties.
Example: "After months of negotiation, a protocol was signed to ensure cooperation between the two countries."
Alternatives: "an agreement was reached" or "a treaty was established."
He said a protocol was signed then to govern future negotiations between the two sides.
On Nov. 30, 1956, a protocol was signed specifying tasks the CEA and the Defense Ministry would perform.
After secret talks in Switzerland, in 2009 a protocol was signed with the hope of restoring diplomatic ties and reopening of the borders.
A Protocol was signed by M&M/Mars in 2001 pledging to eliminate child labor in worldwide cocoa by July 2005.
In 1992, a protocol was signed on cooperation in the field of nuclear energy between Iran and China, and an agreement on the "use of nuclear energy for peaceful purposes" between Iran and Russia.
American diplomat Averell Harriman and Churchill's minister Lord Beaverbrook led a special mission to Moscow and soon a confidential protocol was signed in which the US and Britain agreed to send military supplies to the Soviet Union.
Đjukanović has been instrumental in pulling his country to the verge of Nato membership – an accession protocol was signed in May – which has dashed Russian hopes of securing a naval foothold on the Adriatic.
And yet, trusting the science, and with international leadership, an agreement – the Montreal Protocol – was signed within two years of the discovery of a hole in the ozone layer in the southern polar region.
In September, a ceasefire agreement called the Minsk Protocol was signed, but according to Aleksandr Shumakov, a local businessman turned commander, "There hasn't been a day of ceasefire here".
After the Kyoto Protocol was signed, a number of technical issues regarding the use of carbon plantations in achieving the country commitments remained open.
September 16 marks the International Day for the Preservation of the Ozone Layer, commemorated as the anniversary of that day in 1987 when the Montreal Protocol was signed, an international treaty created to limit and eventually ban CFCs and other substances that were discovered to have been depleting our ozone.
