https://arvsjo.r-universe.dev/ivtoolshttps://arvsjo.r-universe.dev/api/packages/ivtoolshttps://arvsjo.r-universe.dev/ivtools/ivtools.pdfhttps://arvsjo.r-universe.dev/ivtools/doc/manual.htmlhttps://arvsjo.r-universe.dev/ivtools/NEWShttps://arvsjo.r-universe.dev/ivtools/NEWS.txthttps://arvsjo.r-universe.dev/ivtools/citationhttps://arvsjo.r-universe.dev/ivtools/citation.txthttps://arvsjo.r-universe.dev/ivtools/citation.cff