https://www.youtube.com/watch?v=4N2tnP1sYpY&list=RD_OKs2MWaBcA&start_radio=1
https://es.slideshare.net/smerino/esquema-el-imperialismo-15590220
https://www.slideshare.net/anunez12/imperialisme-1870-1914-46903305