You may not have notice when you were copy-pasting those links, the ONE STORY that was actually about the pay gap and had any data was about worldwide pay in developed nations. Women in most European countries have been making the same as men for decades. Hell, even in little countries like Serbia, there's been pay equity for over half a century. The other two stories were op-ed pieces by people who presented evidence, only feelings.
If you look up at the headline of this story, you will notice that it's, "Apple, Facebook, IBM, and Microsoft Sign White House Pledge For Equal Pay". Get that? White House pledge. That means US. And brother, there is absolutely a pay gap in the US. Don't believe me, listen to what those filthy SJW Socialists over at the Wall Street Journal had to say: