NASA
Nasa: The Space Place: What's a Barycenter?
This site from NASA helps in explaining a barycenter. "In the case of the Earth and the Sun, both bodies actually revolve, or spin, around the center of the mass between them. This point is called the barycenter."
Other
Gobierno De Navarra: Puntos Y Rectas Notables De Un Triangle
Learn how to construct the bisectors, median and altitude of a triangle.
Other
Christopher Crockett: The Astronomy Word of the Week Is "Barycenter"
While astronomers and philosophers have long mused on the possibility of other solar systems, the first planets confirmed to orbit a star other than our Sun weren't found until 1992. The reason it took so long is that it's really hard!...