diff --git a/R/data.R b/R/data.R
index 59c0031..f97b521 100644
--- a/R/data.R
+++ b/R/data.R
@@ -1,7 +1,7 @@
 
 #' Principal components of scRNA-Seq of mouse brain cells
 #'
-#' Single-cell RNA-Seq gene expression of 2,816 mouse brain cells (Zeisel, 2015). The top 10 principal components were produced using the steps in the \href{http://bioconductor.org/books/3.13/OSCA.workflows/zeisel-mouse-brain-strt-seq.html}{Bioconductor OSCA workflow}.
+#' Single-cell RNA-Seq gene expression of 2,816 mouse brain cells (Zeisel, 2015). The top 10 principal components were produced using the steps in the \href{https://bioconductor.org/books/3.13/OSCA.workflows/zeisel-mouse-brain-strt-seq.html}{Bioconductor OSCA workflow}.
 #'
 #' @format A data frame with 2,816 rows representing brain cells and 11 columns:
 #' \describe{
diff --git a/man/zeiselPC.Rd b/man/zeiselPC.Rd
index 7444ce7..1ca4254 100644
--- a/man/zeiselPC.Rd
+++ b/man/zeiselPC.Rd
@@ -24,7 +24,7 @@ A data frame with 2,816 rows representing brain cells and 11 columns:
 data(zeiselPC)
 }
 \description{
-Single-cell RNA-Seq gene expression of 2,816 mouse brain cells (Zeisel, 2015). The top 10 principal components were produced using the steps in the \href{http://bioconductor.org/books/3.13/OSCA.workflows/zeisel-mouse-brain-strt-seq.html}{Bioconductor OSCA workflow}.
+Single-cell RNA-Seq gene expression of 2,816 mouse brain cells (Zeisel, 2015). The top 10 principal components were produced using the steps in the \href{https://bioconductor.org/books/3.13/OSCA.workflows/zeisel-mouse-brain-strt-seq.html}{Bioconductor OSCA workflow}.
 }
 \examples{
 data(zeiselPC)