The Article 15 of the Shadow Proclamation, (TV: The Christmas Invasion) also spelt Article Fifteen of the Shadow Proclamation, dealt with murder not being a rule of war.
The Twelfth Doctor tried to invoke this article to a Ba-El Cratt. (PROSE: Diamond Dogs)
Rose Tyler, unaware of this article, addressed the Sycorax according to it when attempting to speak in the Tenth Doctor's place, (TV: The Christmas Invasion) presumably attempting to recall Convention 15, which the Ninth Doctor had used in her presence. (TV: Rose)