diff --git a/R/crossing_of_crossK.R b/R/crossing_of_crossK.R
index a0d7e00..68e3286 100644
--- a/R/crossing_of_crossK.R
+++ b/R/crossing_of_crossK.R
@@ -8,7 +8,7 @@
 #'   two curves. Columns contain "r", "border" and "theo".
 #'
 #' @return A number. The percentage of the crossing position of the specified
-#'   distance.
+#'   distance. Returns NA when the crossing happens too close to the y axis (<4%). 
 #' @export
 #'
 #' @examples
diff --git a/man/crossing_of_crossK.Rd b/man/crossing_of_crossK.Rd
index 90e6682..b441b0b 100644
--- a/man/crossing_of_crossK.Rd
+++ b/man/crossing_of_crossK.Rd
@@ -13,7 +13,7 @@ two curves. Columns contain "r", "border" and "theo".}
 }
 \value{
 A number. The percentage of the crossing position of the specified
-  distance.
+  distance. Returns NA when the crossing happens too close to the y axis (<4%).
 }
 \description{
 Determine if there is a crossing in the cross K curves, to