diff --git a/NAMESPACE b/NAMESPACE
index a2f6ef20..c6686fa8 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -188,4 +188,12 @@ import(ggplot2)
 import(plot3D)
 importFrom(Rcpp,sourceCpp)
 importFrom(emoa,nondominated_points)
+importFrom(grDevices,colorRampPalette)
+importFrom(graphics,abline)
+importFrom(graphics,contour)
+importFrom(graphics,grid)
+importFrom(graphics,image)
+importFrom(graphics,plot)
+importFrom(graphics,points)
+importFrom(stats,reformulate)
 useDynLib(smoof)
diff --git a/R/zzz.R b/R/zzz.R
index fcf272fc..a3aaef85 100644
--- a/R/zzz.R
+++ b/R/zzz.R
@@ -7,4 +7,7 @@
 #' @useDynLib smoof
 #' @importFrom emoa nondominated_points
 #' @importFrom Rcpp sourceCpp
+#' @importFrom grDevices colorRampPalette
+#' @importFrom graphics abline contour grid image plot points
+#' @importFrom stats reformulate
 NULL