diff --git a/part.go b/part.go
index c22740c..d58bf9c 100644
--- a/part.go
+++ b/part.go
@@ -7,22 +7,6 @@ import (
 	"strings"
 )
 
-// CompressionOption is an enumerable for the different compression options.
-type CompressionOption int
-
-const (
-	// CompressionNone disables the compression.
-	CompressionNone CompressionOption = iota - 1
-	// CompressionNormal is optimized for a reasonable compromise between size and performance.
-	CompressionNormal
-	// CompressionMaximum is optimized for size.
-	CompressionMaximum
-	// CompressionFast is optimized for performance.
-	CompressionFast
-	// CompressionSuperFast is optimized for super performance.
-	CompressionSuperFast
-)
-
 // A Part is a stream of bytes defined in ISO/IEC 29500-2 §9.1..
 // Parts are analogous to a file in a file system or to a resource on an HTTP server.
 // The part properties will be validated before writing or reading from disk.
diff --git a/relationship.go b/relationship.go
index 8dfdaf5..dd7855b 100644
--- a/relationship.go
+++ b/relationship.go
@@ -24,19 +24,6 @@ const (
 
 const externalMode = "External"
 
-const (
-	// RelTypeMetaDataCoreProps defines a core properties relationship.
-	RelTypeMetaDataCoreProps = "http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties"
-	// RelTypeDigitalSignature defines a digital signature relationship.
-	RelTypeDigitalSignature = "http://schemas.openxmlformats.org/package/2006/relationships/digital-signature/signature"
-	// RelTypeDigitalSignatureOrigin defines a digital signature origin relationship.
-	RelTypeDigitalSignatureOrigin = "http://schemas.openxmlformats.org/package/2006/relationships/digital-signature/origin"
-	// RelTypeDigitalSignatureCert defines a digital signature certificate relationship.
-	RelTypeDigitalSignatureCert = "http://schemas.openxmlformats.org/package/2006/relationships/digital-signature/certificate"
-	// RelTypeThumbnail defines a thumbnail relationship.
-	RelTypeThumbnail = "http://schemas.openxmlformats.org/package/2006/relationships/metadata/thumbnail"
-)
-
 // Relationship is used to express a relationship between a source and a target part.
 // The only way to create a Relationship, is to call the Part.CreateRelationship()
 // or Package.CreateRelationship(). A relationship is owned by a part or by the package itself.
diff --git a/writer.go b/writer.go
index 6d3cd00..a2a6f20 100644
--- a/writer.go
+++ b/writer.go
@@ -11,6 +11,22 @@ import (
 
 const opcCtx = "opc"
 
+// CompressionOption is an enumerable for the different compression options.
+type CompressionOption int
+
+const (
+	// CompressionNone disables the compression.
+	CompressionNone CompressionOption = iota - 1
+	// CompressionNormal is optimized for a reasonable compromise between size and performance.
+	CompressionNormal
+	// CompressionMaximum is optimized for size.
+	CompressionMaximum
+	// CompressionFast is optimized for performance.
+	CompressionFast
+	// CompressionSuperFast is optimized for super performance.
+	CompressionSuperFast
+)
+
 // Writer implements a OPC file writer.
 type Writer struct {
 	p    *Package
@@ -26,7 +42,7 @@ func NewWriter(w io.Writer) *Writer {
 // Flush flushes any buffered data to the underlying writer.
 // Part metadata, relationships, content types and other OPC related files won't be flushed.
 // Calling Flush is not normally necessary; calling Close is sufficient.
-// Useful to do simultaneos writing and reading.
+// Useful to do simultaneous writing and reading.
 func (w *Writer) Flush() error {
 	return w.w.Flush()
 }