https://hugogogo.r-universe.dev/naturalhttps://hugogogo.r-universe.dev/api/packages/naturalhttps://hugogogo.r-universe.dev/natural/natural.pdfhttps://hugogogo.r-universe.dev/natural/doc/manual.htmlhttps://hugogogo.r-universe.dev/natural/NEWShttps://hugogogo.r-universe.dev/natural/NEWS.txthttps://hugogogo.r-universe.dev/natural/citationhttps://hugogogo.r-universe.dev/natural/citation.txthttps://hugogogo.r-universe.dev/natural/citation.cffhttps://hugogogo.r-universe.dev/natural/doc/using_natural.Rmdhttps://hugogogo.r-universe.dev/articles/natural/using_natural.html