https://cajoterbraak.r-universe.dev/PRChttps://cajoterbraak.r-universe.dev/api/packages/PRChttps://cajoterbraak.r-universe.dev/PRC/PRC.pdfhttps://cajoterbraak.r-universe.dev/PRC/doc/manual.htmlhttps://cajoterbraak.r-universe.dev/PRC/citationhttps://cajoterbraak.r-universe.dev/PRC/citation.txthttps://cajoterbraak.r-universe.dev/PRC/citation.cffhttps://cajoterbraak.r-universe.dev/PRC/doc/smoothPRC.Rmdhttps://cajoterbraak.r-universe.dev/articles/PRC/smoothPRC.html