diff --git a/src/main/java/eu/dnetlib/apps/oai/OaiService.java b/src/main/java/eu/dnetlib/apps/oai/OaiService.java
index aea83bf..5fce9bd 100644
--- a/src/main/java/eu/dnetlib/apps/oai/OaiService.java
+++ b/src/main/java/eu/dnetlib/apps/oai/OaiService.java
@@ -165,9 +165,9 @@ public class OaiService {
 		return listMetadataFormats()
 			.stream()
 			.filter(f -> f.getMetadataPrefix().equalsIgnoreCase(metadataPrefix))
-			.map(OaiMetadataFormat::getXslt)
+			.map(OaiMetadataFormat::getXsltPath)
+			.map(xsltPath -> this.xsltTransformerFactory.getTransformer(xsltPath, null))
 			.findFirst()
-			.map(xslt -> this.xsltTransformerFactory.getTransformerByXSLT(xslt, null))
 			.orElseThrow(() -> new RuntimeException("Invalid metadata format: " + metadataPrefix));
 	}
 
diff --git a/src/main/java/eu/dnetlib/apps/oai/domain/OaiMetadataFormat.java b/src/main/java/eu/dnetlib/apps/oai/domain/OaiMetadataFormat.java
index bfc4b85..5eda62a 100644
--- a/src/main/java/eu/dnetlib/apps/oai/domain/OaiMetadataFormat.java
+++ b/src/main/java/eu/dnetlib/apps/oai/domain/OaiMetadataFormat.java
@@ -12,7 +12,7 @@ public class OaiMetadataFormat implements Serializable {
 
 	private String metadataNamespace;
 
-	private String xslt;
+	private String xsltPath;
 
 	public String getMetadataPrefix() {
 		return this.metadataPrefix;
@@ -38,12 +38,12 @@ public class OaiMetadataFormat implements Serializable {
 		this.metadataNamespace = metadataNamespace;
 	}
 
-	public String getXslt() {
-		return this.xslt;
+	public String getXsltPath() {
+		return this.xsltPath;
 	}
 
-	public void setXslt(final String xslt) {
-		this.xslt = xslt;
+	public void setXslt(final String xsltPath) {
+		this.xsltPath = xsltPath;
 	}
 
 }
diff --git a/src/main/java/eu/dnetlib/apps/oai/domain/OaiSet.java b/src/main/java/eu/dnetlib/apps/oai/domain/OaiSet.java
index a61fea9..a7dc6a8 100644
--- a/src/main/java/eu/dnetlib/apps/oai/domain/OaiSet.java
+++ b/src/main/java/eu/dnetlib/apps/oai/domain/OaiSet.java
@@ -12,8 +12,6 @@ public class OaiSet implements Serializable {
 
 	private String description;
 
-	private String dsId;
-
 	public String getSetSpec() {
 		return this.setSpec;
 	}
@@ -38,16 +36,4 @@ public class OaiSet implements Serializable {
 		this.description = description;
 	}
 
-	public String getDsId() {
-		return this.dsId;
-	}
-
-	public void setDsId(final String dsId) {
-		this.dsId = dsId;
-	}
-
-	public static long getSerialversionuid() {
-		return serialVersionUID;
-	}
-
 }
diff --git a/src/main/java/eu/dnetlib/apps/oai/utils/XsltTransformerFactory.java b/src/main/java/eu/dnetlib/apps/oai/utils/XsltTransformerFactory.java
index d735d95..585c61a 100644
--- a/src/main/java/eu/dnetlib/apps/oai/utils/XsltTransformerFactory.java
+++ b/src/main/java/eu/dnetlib/apps/oai/utils/XsltTransformerFactory.java
@@ -1,5 +1,6 @@
 package eu.dnetlib.apps.oai.utils;
 
+import java.io.FileInputStream;
 import java.io.StringWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -26,7 +27,7 @@ import net.sf.saxon.s9api.XsltTransformer;
 @Component
 public class XsltTransformerFactory {
 
-	public Function<String, String> getTransformerByXSLT(final String xsltText, final Map<String, Object> params) {
+	public Function<String, String> getTransformer(final String xsltPath, final Map<String, Object> params) {
 		final Processor processor = new Processor(false);
 
 		final List<XmlProcessingError> errorList = new ArrayList<>();
@@ -35,8 +36,8 @@ public class XsltTransformerFactory {
 		comp.setErrorList(errorList);
 		params.forEach((k, v) -> comp.setParameter(new QName(k), XdmAtomicValue.makeAtomicValue(v)));
 
-		try {
-			final XsltExecutable xslt = comp.compile(new StreamSource(IOUtils.toInputStream(xsltText, StandardCharsets.UTF_8)));
+		try (FileInputStream fileInputStream = new FileInputStream(xsltPath)) {
+			final XsltExecutable xslt = comp.compile(new StreamSource(fileInputStream));
 			return xml -> {
 				try {
 					final XdmNode source = processor
diff --git a/src/main/resources/oai-metadata-formats.json b/src/main/resources/oai-metadata-formats.json
index fe51488..150152b 100644
--- a/src/main/resources/oai-metadata-formats.json
+++ b/src/main/resources/oai-metadata-formats.json
@@ -1 +1,8 @@
-[]
+[
+	{
+		"metadataPrefix"   : "oai_dc",
+		"metadataSchema"   : "http://www.openarchives.org/OAI/2.0/oai_dc.xsd",
+		"metadataNamespace": "http://www.openarchives.org/OAI/2.0/oai_dc/",
+		"xsltPath"         : "xslt/raw_to_dc.xslt"
+	}
+]