https://grantmcdermott.r-universe.dev/lfe2fixesthttps://grantmcdermott.r-universe.dev/api/packages/lfe2fixesthttps://grantmcdermott.r-universe.dev/lfe2fixest/lfe2fixest.pdfhttps://grantmcdermott.r-universe.dev/lfe2fixest/doc/manual.htmlhttps://grantmcdermott.r-universe.dev/lfe2fixest/NEWShttps://grantmcdermott.r-universe.dev/lfe2fixest/NEWS.txthttps://grantmcdermott.r-universe.dev/lfe2fixest/citationhttps://grantmcdermott.r-universe.dev/lfe2fixest/citation.txthttps://grantmcdermott.r-universe.dev/lfe2fixest/citation.cff