27 A.C. - 476 D.C
% complete
http://files.centro-demaestros-cuautitlan1524.webnode.mx/200000125-3eebe40e26/Ecolog%C3%ADa%20Humana.pdf
500 A.C
https://www.redalyc.org/pdf/1910/191019350008.pdf
1500 - 1820
http://agro.unc.edu.ar/~extrural/HerreraEspacioTecn.pdf
1815 - 1871
https://s3.amazonaws.com/academia.edu.documents/35651592/152995116-Ernest-Gellner-Naciones-y-nacionalismo-pdf.pdf?response-content-disposition=inline%3B%20filename%3DErnest-Gellner-Naciones-y-nacionalismo-p.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20190829%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20190829T153843Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=c92d887cac1ecc453ee999a299fb98c1c4b3277f8e25a44daf6a0643cd0b3a12
1848 - 1989
https://books.google.es/books?hl=es&lr=&id=cSvEDgAAQBAJ&oi=fnd&pg=PR2&dq=principios+de+comunismo&ots=_QI_eeMtDM&sig=gPUOXAOL51Eg61cm7RTbWCSsvik#v=onepage&q=principios%20de%20comunismo&f=false
1930 - 2019
http://www.revistaeconomiacritica.org/sites/default/files/5_REC13_Nota_J_Catalan.pdf
1937 - 1945
https://www.earthmagazine.org/article/june-9-1938-huang-he-diversion-largest-act-environmental-warfare-history
1962
http://www.scielo.org.mx/scielo.php?pid=S0187-893X2012000200009&script=sci_abstract&tlng=en
1970
https://www.independent.co.uk/news/uk/politics/the-green-party-a-short-history-9878649.html
1986
https://www.sciencedirect.com/science/article/pii/S004896971301173X