diff --git a/export.go b/export.go
index 6edf950..80f943f 100644
--- a/export.go
+++ b/export.go
@@ -130,15 +130,15 @@ func (graph *Graph) ExportVerticesToFile(fname string) error {
 // 	weight - float64, Weight of an shortcut
 // 	via_vertex_id - int64, ID of vertex through which the shortcut exists
 func (graph *Graph) ExportShortcutsToFile(fname string) error {
-	fileContractions, err := os.Create(fname)
+	fileShortcuts, err := os.Create(fname)
 	if err != nil {
 		return errors.Wrap(err, "Can't create shortcuts file")
 	}
-	defer fileContractions.Close()
-	writerContractions := csv.NewWriter(fileContractions)
-	defer writerContractions.Flush()
-	writerContractions.Comma = ';'
-	err = writerContractions.Write([]string{"from_vertex_id", "to_vertex_id", "weight", "via_vertex_id"})
+	defer fileShortcuts.Close()
+	writerShortcuts := csv.NewWriter(fileShortcuts)
+	defer writerShortcuts.Flush()
+	writerShortcuts.Comma = ';'
+	err = writerShortcuts.Write([]string{"from_vertex_id", "to_vertex_id", "weight", "via_vertex_id"})
 	if err != nil {
 		return errors.Wrap(err, "Can't write header to shortucts file")
 	}
@@ -147,7 +147,7 @@ func (graph *Graph) ExportShortcutsToFile(fname string) error {
 		for targetVertexInternal, viaNodeInternal := range to {
 			targetVertexExternal := graph.Vertices[targetVertexInternal].Label
 			viaNodeExternal := graph.Vertices[viaNodeInternal.ViaVertex].Label
-			err = writerContractions.Write([]string{
+			err = writerShortcuts.Write([]string{
 				fmt.Sprintf("%d", sourceVertexExternal),
 				fmt.Sprintf("%d", targetVertexExternal),
 				strconv.FormatFloat(viaNodeInternal.Cost, 'f', -1, 64),
diff --git a/graph.go b/graph.go
index 539174b..48bc280 100644
--- a/graph.go
+++ b/graph.go
@@ -116,9 +116,10 @@ func (graph *Graph) AddEdge(from, to int64, weight float64) error {
 
 // AddShortcut Adds new shortcut between two vertices
 //
-// from User's definied ID of first vertex of shortcut
-// to User's definied ID of last vertex of shortcut
-// weight User's definied weight of shortcut
+// from - User's definied ID of first vertex of shortcut
+// to - User's definied ID of last vertex of shortcut
+// via - User's defined ID of vertex through which the shortcut exists
+// weight - User's definied weight of shortcut
 //
 func (graph *Graph) AddShortcut(from, to, via int64, weight float64) error {
 	if graph.frozen {
diff --git a/import.go b/import.go
index 2e1c561..573f616 100644
--- a/import.go
+++ b/import.go
@@ -30,6 +30,7 @@ func ImportFromFile(edgesFname, verticesFname, contractionsFname string) (*Graph
 	if err != nil {
 		return nil, err
 	}
+	defer file.Close()
 	reader := csv.NewReader(file)
 	reader.Comma = ';'
 
@@ -81,6 +82,7 @@ func ImportFromFile(edgesFname, verticesFname, contractionsFname string) (*Graph
 	if err != nil {
 		return nil, err
 	}
+	defer fileVertices.Close()
 	readerVertices := csv.NewReader(fileVertices)
 	readerVertices.Comma = ';'
 
@@ -118,20 +120,21 @@ func ImportFromFile(edgesFname, verticesFname, contractionsFname string) (*Graph
 	}
 
 	// Read contractions
-	fileContractions, err := os.Open(contractionsFname)
+	fileShortcuts, err := os.Open(contractionsFname)
 	if err != nil {
 		return nil, err
 	}
-	readerContractions := csv.NewReader(fileContractions)
-	readerContractions.Comma = ';'
+	defer fileShortcuts.Close()
+	readerShortcuts := csv.NewReader(fileShortcuts)
+	readerShortcuts.Comma = ';'
 	// Skip header of CSV-file
-	_, err = readerContractions.Read()
+	_, err = readerShortcuts.Read()
 	if err != nil {
 		return nil, err
 	}
 	// Read file line by line
 	for {
-		record, err := readerContractions.Read()
+		record, err := readerShortcuts.Read()
 		if err == io.EOF {
 			break
 		}