https://umich-cphds.r-universe.dev/gigghttps://umich-cphds.r-universe.dev/api/packages/gigghttps://umich-cphds.r-universe.dev/gigg/gigg.pdfhttps://umich-cphds.r-universe.dev/gigg/doc/manual.htmlhttps://umich-cphds.r-universe.dev/gigg/citationhttps://umich-cphds.r-universe.dev/gigg/citation.txthttps://umich-cphds.r-universe.dev/gigg/citation.cff