diff --git a/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDExporter.java b/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDExporter.java
index daee308e..19467a47 100644
--- a/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDExporter.java
+++ b/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDExporter.java
@@ -135,15 +135,15 @@ public class ZUGFeRDExporter implements Closeable {
 	 * @param filename
 	 * @param filecontent
 	 */
-	public void addAdditionalFile(String filename, byte[] xml) {
-		additionalFiles.put(filename, xml);
+	public void addAdditionalFile(String filename, byte[] filecontent) {
+		additionalFiles.put(filename, filecontent);
 
 	}
 
 	/***
 	 * internal helper function: get namespace for given zugferd or factur-x version
-	 * @param ver
-	 * @return
+	 * @param ver the ZUGFeRD version
+	 * @return the URN of the namespace
 	 */
 	public String getNamespaceForVersion(int ver) {
 		if (isFacturX) {
@@ -160,8 +160,8 @@ public class ZUGFeRDExporter implements Closeable {
 
 	/***
 	 * internal helper: returns the namespace prefix for the given zf/fx version number
-	 * @param ver
-	 * @return
+	 * @param ver the zf/fx version
+	 * @return the namespace prefix as string, without colon
 	 */
 	public String getPrefixForVersion(int ver) {
 		if (isFacturX) {
@@ -173,8 +173,8 @@ public class ZUGFeRDExporter implements Closeable {
 
 	/***
 	 * internal helper: return the name of the file attachment for the given zf/fx version
-	 * @param ver
-	 * @return
+	 * @param ver the zf/fx version
+	 * @return the filename of the file to be embedded
 	 */
 	public String getFilenameForVersion(int ver) {
 		if (isFacturX) {
diff --git a/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDImporter.java b/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDImporter.java
index 117d0e5d..9a974d6a 100644
--- a/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDImporter.java
+++ b/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDImporter.java
@@ -38,9 +38,6 @@ import org.xml.sax.SAXException;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
-import javax.xml.transform.*;
-import javax.xml.transform.dom.DOMSource;
-import javax.xml.transform.stream.StreamResult;
 import javax.xml.xpath.XPath;
 import javax.xml.xpath.XPathExpressionException;
 import javax.xml.xpath.XPathFactory;
@@ -186,7 +183,7 @@ public class ZUGFeRDImporter {
 	/**
 	 * Skips over a BOM at the beginning of the given ByteArrayInputStream, if one exists.
 	 * @param is the ByteArrayInputStream used
-	 * @throws IOException
+	 * @throws IOException if can not be read from is
 	 * @see <a href="https://www.w3.org/TR/xml/#sec-guessing">Autodetection of Character Encodings</a>
 	 */
 	private int guessBOMSize(ByteArrayInputStream is) throws IOException {
@@ -335,6 +332,7 @@ public class ZUGFeRDImporter {
 
 	/**
 	 * @param meta raw XML to be set
+	 * @throws IOException if raw can not be set
 	 */
 	public void setMeta(String meta) throws IOException {
 		setRawXML(meta.getBytes());