diff --git a/DESCRIPTION b/DESCRIPTION
index f12b16d..c88278d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -17,4 +17,5 @@ Imports:
     graphics,
     utils
 License: GPL-2 | file LICENSE
+LazyData: true
 RoxygenNote: 6.0.1
diff --git a/R/biclique.R b/R/biclique.R
index efb9809..d8d29bd 100644
--- a/R/biclique.R
+++ b/R/biclique.R
@@ -16,9 +16,9 @@
 #' @param envir biclique environment
 #'
 #' @examples
-#' bicliques = bi.clique("example1.el")
-#' bicliques = bi.clique("example1.el", 3, 2)
-#' bicliques = bi.clique("example4.bmat", filetype = 1)
+#' bicliques = bi.clique(system.file("extdata", "example1.el", package = "biclique"))
+#' bicliques = bi.clique(system.file("extdata", "example1.el", package = "biclique"), 3, 2)
+#' bicliques = bi.clique(system.file("extdata", "example4.bmat", package = "biclique"), filetype = 1)
 #' # check a biclique
 #' bicliques$biclique1
 #'
@@ -87,8 +87,8 @@ bi.clique <- function(filename, lleast = 1, rleast = 1, version = 1, filetype =
 #' @param filetype Input file format <default = 0>. 0-edge list, 1-binary matrix.
 #'
 #' @examples
-#' degreelist = bi.degree("example1.el")
-#' degreelist = bi.degree("example4.bmat", 1)
+#' degreelist = bi.degree(system.file("extdata", "example1.el", package = "biclique")) 
+#' degreelist = bi.degree(system.file("extdata", "example4.bmat", package = "biclique"), 1)
 #' #get the vertex degree
 #' degreelist['A']
 #'
@@ -123,7 +123,7 @@ bi.degree <- function(filename, filetype = 0)
 #' @param envir biclique environment
 #'
 #' @examples
-#' bicliques = bi.clique("example1.el")
+#' bicliques = bi.clique(system.file("extdata", "example1.el", package = "biclique"))
 #' bi.print()
 #'
 #' @importFrom graphics barplot lines points text
@@ -161,8 +161,8 @@ bi.print <- function(envir = .GlobalEnv$.bienv)
 #' @param filetype Input file format <default = 0>. 0-edge list, 1-binary matrix.
 #'
 #' @examples
-#' bi.format("example2.el")
-#' bi.format("example5.bmat", 1)
+#' bi.format(system.file("extdata", "example2.el", package = "biclique"))
+#' bi.format(system.file("extdata", "example5.bmat", package = "biclique"), 1)
 #'
 #' @importFrom utils read.table write.table
 #' @export
diff --git a/man/bi.clique.Rd b/man/bi.clique.Rd
index c59c93d..2979ef9 100644
--- a/man/bi.clique.Rd
+++ b/man/bi.clique.Rd
@@ -29,9 +29,9 @@ This package supports edgelist and binary matrix file format.
 Two versions of algorithms are implemented in this function, you can choose either one to get bicliques.
 }
 \examples{
-bicliques = bi.clique("example1.el")
-bicliques = bi.clique("example1.el", 3, 2)
-bicliques = bi.clique("example4.bmat", filetype = 1)
+bicliques = bi.clique(system.file("extdata", "example1.el", package = "biclique"))
+bicliques = bi.clique(system.file("extdata", "example1.el", package = "biclique"), 3, 2)
+bicliques = bi.clique(system.file("extdata", "example4.bmat", package = "biclique"), filetype = 1)
 # check a biclique
 bicliques$biclique1
 
diff --git a/man/bi.degree.Rd b/man/bi.degree.Rd
index c2b2496..cef29c7 100644
--- a/man/bi.degree.Rd
+++ b/man/bi.degree.Rd
@@ -15,8 +15,8 @@ bi.degree(filename, filetype = 0)
 This function will output the degree of each vertex.
 }
 \examples{
-degreelist = bi.degree("example1.el")
-degreelist = bi.degree("example4.bmat", 1)
+degreelist = bi.degree(system.file("extdata", "example1.el", package = "biclique")) 
+degreelist = bi.degree(system.file("extdata", "example4.bmat", package = "biclique"), 1)
 #get the vertex degree
 degreelist['A']
 
diff --git a/man/bi.format.Rd b/man/bi.format.Rd
index 56d3d35..cba404d 100644
--- a/man/bi.format.Rd
+++ b/man/bi.format.Rd
@@ -20,7 +20,7 @@ If your input file already have those entries, pleast don't run this command. Ot
 Please also note that no comment characters are allowed in the input file.
 }
 \examples{
-bi.format("example2.el")
-bi.format("example5.bmat", 1)
+bi.format(system.file("extdata", "example2.el", package = "biclique"))
+bi.format(system.file("extdata", "example5.bmat", package = "biclique"), 1)
 
 }
diff --git a/man/bi.print.Rd b/man/bi.print.Rd
index e7f3d0f..09e77ab 100644
--- a/man/bi.print.Rd
+++ b/man/bi.print.Rd
@@ -13,7 +13,7 @@ bi.print(envir = .GlobalEnv$.bienv)
 You can pass results from function bi.clique to this function to visualize the bicliques.
 }
 \examples{
-bicliques = bi.clique("example1.el")
+bicliques = bi.clique(system.file("extdata", "example1.el", package = "biclique"))
 bi.print()
 
 }