diff --git a/pkg/graph/post.go b/pkg/graph/post.go
index 5053858..054d124 100644
--- a/pkg/graph/post.go
+++ b/pkg/graph/post.go
@@ -27,5 +27,5 @@ type Post interface {
 	CheckPostNodeExistsBySourceURL(ctx context.Context, sourceUrl string) (*models.AnthrovePost, bool, error)
 
 	// LinkPostWithSource establishes a link between a post and a source in the OtterSpace graph.
-	LinkPostWithSource(ctx context.Context, anthrovePostID models.AnthrovePostID, anthroveSourceDomain string, anthrovePostRelationship *models.AnthrovePostRelationship) error
+	LinkPostWithSource(ctx context.Context, anthrovePostID models.AnthrovePostID, anthroveSourceDomain models.AnthroveSourceDomain, anthrovePostRelationship *models.AnthrovePostRelationship) error
 }
diff --git a/pkg/graph/source.go b/pkg/graph/source.go
index ddadc28..2d133d4 100644
--- a/pkg/graph/source.go
+++ b/pkg/graph/source.go
@@ -23,7 +23,7 @@ type Source interface {
 
 	// GetSourceLinkForSpecifiedUser GetSourceLinkForUser retrieves the links between a user and a specific source in the OtterSpace graph.
 	// It returns a map of source domains to user-source relationships, and an error if the operation fails.
-	GetSourceLinkForSpecifiedUser(ctx context.Context, anthroveUserID models.AnthroveUserID, sourceDisplayName string) (map[string]models.AnthroveUserRelationship, error)
+	GetSourceLinkForSpecifiedUser(ctx context.Context, anthroveUserID models.AnthroveUserID, sourceDisplayName models.AnthroveSourceDisplayName) (map[string]models.AnthroveUserRelationship, error)
 
 	// GetAllSources returns a list of Sources in the database
 	GetAllSources(ctx context.Context) ([]models.AnthroveSource, error)