แหล่งที่มา WikiPedia: กูมาร์คัฆ http://www.gobernandoconlagente.gob.gt/cache/media... //doi.org/10.2307%2F280211 //www.jstor.org/stable/280211 //tools.wmflabs.org/geohack/geohack.php?pagename=%... //www.worldcat.org/oclc/253481949 //www.worldcat.org/oclc/34658843 //www.worldcat.org/oclc/57577446 //www.worldcat.org/oclc/59432778 https://archive.org/details/ancientmaya0006shar
