diff --git a/R/footnote.R b/R/footnote.R
index 8863327..5e9201f 100644
--- a/R/footnote.R
+++ b/R/footnote.R
@@ -26,6 +26,9 @@
 #' @param alphabet_title Section header for alphabet footnotes. Default is "".
 #' @param symbol_title Section header for symbol footnotes. Default is "".
 #'
+#' @examples x <- mtcars[1:5, 1:5]
+#' footnote(knitr::kable(dt, "html"), alphabet = c("Note a", "Note b"))
+#'
 #' @export
 footnote <- function(kable_input,
                      general = NULL,
diff --git a/R/footnote_marker.R b/R/footnote_marker.R
index df54339..beb1c4e 100644
--- a/R/footnote_marker.R
+++ b/R/footnote_marker.R
@@ -11,6 +11,11 @@
 #' @param format Either `html` or `latex`. All functions here can read
 #' default value from global option `knitr.table.format`.
 #'
+#' @examples x <- mtcars[1:5, 1:5]
+#' colnames(dt)[1] <- paste0("mpg", footnote_marker_alphabet(2, "html"))
+#' rownames(dt)[2] <- paste0(rownames(dt)[2], footnote_marker_alphabet(1, "html"))
+#' footnote(knitr::kable(dt, "html"), alphabet = c("Note a", "Note b"))
+#'
 #' @export
 footnote_marker_number <- function(x, format) {
   if (missing(format) || is.null(format)) {
diff --git a/R/row_spec.R b/R/row_spec.R
index d58493c..deedf68 100644
--- a/R/row_spec.R
+++ b/R/row_spec.R
@@ -33,7 +33,7 @@
 row_spec <- function(kable_input, row,
                      bold = FALSE, italic = FALSE, monospace = FALSE,
                      color = NULL, background = NULL, align = NULL,
-                     font_size = NULL, angle = NULL, extra_css) {
+                     font_size = NULL, angle = NULL, extra_css = NULL) {
   if (!is.numeric(row)) {
     stop("row must be numeric. ")
   }
diff --git a/man/footnote.Rd b/man/footnote.Rd
index b2cc29c..8cda4fc 100644
--- a/man/footnote.Rd
+++ b/man/footnote.Rd
@@ -49,3 +49,8 @@
 also possible to specify footnote section header one by one and print
 footnotes as a chunk of texts.
 }
+\examples{
+x <- mtcars[1:5, 1:5]
+footnote(knitr::kable(dt, "html"), alphabet = c("Note a", "Note b"))
+
+}
diff --git a/man/footnote_marker_number.Rd b/man/footnote_marker_number.Rd
index c16664c..1c3ba37 100644
--- a/man/footnote_marker_number.Rd
+++ b/man/footnote_marker_number.Rd
@@ -26,3 +26,10 @@
 \code{format} option here can read default value from global option
 \code{knitr.table.format}.
 }
+\examples{
+x <- mtcars[1:5, 1:5]
+colnames(dt)[1] <- paste0("mpg", footnote_marker_alphabet(2, "html"))
+rownames(dt)[2] <- paste0(rownames(dt)[2], footnote_marker_alphabet(1, "html"))
+footnote(knitr::kable(dt, "html"), alphabet = c("Note a", "Note b"))
+
+}
diff --git a/man/row_spec.Rd b/man/row_spec.Rd
index 0338b13..da3c7b2 100644
--- a/man/row_spec.Rd
+++ b/man/row_spec.Rd
@@ -6,7 +6,7 @@
 \usage{
 row_spec(kable_input, row, bold = FALSE, italic = FALSE,
   monospace = FALSE, color = NULL, background = NULL, align = NULL,
-  font_size = NULL, angle = NULL, extra_css)
+  font_size = NULL, angle = NULL, extra_css = NULL)
 }
 \arguments{
 \item{kable_input}{Output of \code{knitr::kable()} with \code{format} specified}