diff --git a/Gruntfile.js b/Gruntfile.js
index 5212b2e..73e3cc0 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -67,7 +67,11 @@ module.exports = function (grunt) {
 			testConflicts: {
 				src: ['test/src/conflicts/dirname/index.ts'],
 				outDir: 'test/build/conflicts/dirname'
-			}
+			},
+			testDotSlash: {
+				src: ['test/src/dot-slash/index.ts'],
+				outDir: 'test/build/dot-slash'
+      }
 		},
 		mochaTest: {
 			options: {
@@ -92,6 +96,7 @@ module.exports = function (grunt) {
 		'ts:testEs6',
 		'ts:testCommonJs',
 		'ts:testConflicts',
+		'ts:testDotSlash',
 		'run'
 	]);
 
diff --git a/lib/index.ts b/lib/index.ts
index 6e744c4..8446f34 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -183,7 +183,7 @@ export function bundle(options: Options): BundleResult {
             mainFileContent += generatedLine + "\n";
         });
         mainFile = path.resolve(baseDir, "dts-bundle.tmp." + exportName + ".d.ts");
-        fs.writeFileSync(mainFile, mainFileContent, 'utf8');
+        fs.writeFileSync(mainFile, mainFileContent, { encoding: 'utf8' });
     }
 
     trace('\n### find typings ###');
@@ -424,7 +424,7 @@ export function bundle(options: Options): BundleResult {
             }
         }
 
-        fs.writeFileSync(outFile, content, 'utf8');
+        fs.writeFileSync(outFile, content, { encoding: 'utf8' });
         bundleResult.emitted = true;
     } else {
         warning(" XXX Not emit due to exist files not found.")
diff --git a/test/expected/dot-slash/bundle.d.ts b/test/expected/dot-slash/bundle.d.ts
new file mode 100644
index 0000000..7d271eb
--- /dev/null
+++ b/test/expected/dot-slash/bundle.d.ts
@@ -0,0 +1,19 @@
+
+declare module 'bundle' {
+    import { SomeOtherClass } from "bundle/SomeOtherClass";
+    export interface IShouldBeThereOnlyOnce {
+        name: string;
+    }
+    export function getOther(): SomeOtherClass;
+}
+
+declare module 'bundle/SomeOtherClass' {
+    import { IShouldBeThereOnlyOnce } from "bundle/";
+    export class SomeOtherClass {
+        /**
+          * Extract metadata from the given audio file
+          */
+        static saveTheWorld(once: IShouldBeThereOnlyOnce): Promise<any>;
+    }
+}
+
diff --git a/test/src/dot-slash/SomeOtherClass.ts b/test/src/dot-slash/SomeOtherClass.ts
new file mode 100644
index 0000000..ca2f4b5
--- /dev/null
+++ b/test/src/dot-slash/SomeOtherClass.ts
@@ -0,0 +1,11 @@
+import {IShouldBeThereOnlyOnce} from "./";
+
+export class SomeOtherClass {
+
+  /**
+   * Extract metadata from the given audio file
+   */
+  public static saveTheWorld(once: IShouldBeThereOnlyOnce): Promise<any> {
+    return null;
+  }
+}
diff --git a/test/src/dot-slash/index.ts b/test/src/dot-slash/index.ts
new file mode 100644
index 0000000..65fcf51
--- /dev/null
+++ b/test/src/dot-slash/index.ts
@@ -0,0 +1,13 @@
+'use strict';
+
+import {SomeOtherClass} from "./SomeOtherClass";
+
+const other: SomeOtherClass = new SomeOtherClass();
+
+export interface IShouldBeThereOnlyOnce {
+  name: string,
+}
+
+export function getOther(): SomeOtherClass {
+  return null;
+}
diff --git a/test/test.js b/test/test.js
index 25f95dc..504dac0 100644
--- a/test/test.js
+++ b/test/test.js
@@ -532,4 +532,54 @@ describe('dts bundle', function () {
 		]);
 		assert.strictEqual(getFile(actualFile), getFile(expectedFile));
 	});
+
+  (function testit(name, assertion, run) {
+    var buildDir = path.resolve(__dirname, 'build', name);
+    var call = function (done) {
+      var testDir = path.join(tmpDir, name);
+      var expDir = path.join(expectDir, name);
+
+      mkdirp.sync(testDir);
+
+      ncp.ncp(buildDir, testDir, function (err) {
+        if (err) {
+          done(err);
+          return;
+        }
+        assertion(testDir, expDir);
+        done();
+      });
+    };
+
+    var label = 'bundle ' + name;
+
+    if (run === 'skip') {
+      it.skip(label, call);
+    }
+    else if (run === 'only') {
+      it.only(label, call);
+    }
+    else {
+      it(label, call);
+    }
+  })('dot-slash', function (actDir, expDir) {
+    var result = dts.bundle({
+      name: 'bundle',
+      main: path.join(actDir, '../dot-slash', 'index.d.ts'),
+      newline: '\n',
+      verbose: true,
+      headerPath: "none"
+    });
+    var name = 'bundle.d.ts';
+    var actualFile = path.join(actDir, name);
+    assert.isTrue(result.emitted, "not emit " + actualFile);
+    var expectedFile = path.join(expDir, name);
+    assertFiles(actDir, [
+      name,
+      'index.d.ts',
+      'SomeOtherClass.d.ts'
+    ]);
+    assert.strictEqual(getFile(actualFile), getFile(expectedFile));
+  })
+
 });