diff --git a/Sources/include/HTMLElement.h b/Sources/include/HTMLElement.h
index 0975bc2..dcf5372 100644
--- a/Sources/include/HTMLElement.h
+++ b/Sources/include/HTMLElement.h
@@ -53,7 +53,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  The element's attribites.
  */
-@property (nonatomic, strong) NSMutableDictionary *attributes;
+@property (nonatomic, strong) NSMutableDictionary<NSString *, NSString *> *attributes;
 
 /**
  @warning Use one of the initWithTagName: methods instead.
@@ -75,7 +75,7 @@ NS_ASSUME_NONNULL_BEGIN
  @param attributes The attributes.
  @return A new HTML element.
  */
-- (instancetype)initWithTagName:(NSString *)tagName attributes:(NSDictionary *)attributes;
+- (instancetype)initWithTagName:(NSString *)tagName attributes:(NSDictionary<NSString *, NSString *> *)attributes;
 
 /**
  Initializes a new HTML element with the given tag name, namespace, and attributes.
@@ -85,7 +85,7 @@ NS_ASSUME_NONNULL_BEGIN
  @param attributes The attributes.
  @return A new HTML element.
  */
-- (instancetype)initWithTagName:(NSString *)tagName namespace:(HTMLNamespace)htmlNamespace attributes:(NSDictionary *)attributes;
+- (instancetype)initWithTagName:(NSString *)tagName namespace:(HTMLNamespace)htmlNamespace attributes:(NSDictionary<NSString *, NSString *> *)attributes;
 
 /**
  Checks whether this element has an attribute with the given name.
diff --git a/Sources/include/HTMLNode.h b/Sources/include/HTMLNode.h
index dc22705..da1a5c5 100644
--- a/Sources/include/HTMLNode.h
+++ b/Sources/include/HTMLNode.h
@@ -86,7 +86,7 @@ typedef NS_ENUM(unsigned short, HTMLDocumentPosition)
 /**
  A read-only ordered set of child nodes.
  */
-@property (nonatomic, strong, readonly) NSOrderedSet *childNodes;
+@property (nonatomic, strong, readonly) NSOrderedSet<HTMLNode *> *childNodes;
 
 /**
  The first child node, if any.
@@ -220,7 +220,7 @@ typedef NS_ENUM(unsigned short, HTMLDocumentPosition)
 
  @param node The nodes to prepend.
  */
-- (void)prependNodes:(NSArray *)nodes;
+- (void)prependNodes:(NSArray<HTMLNode *> *)nodes;
 
 /**
  Appends the given node to the set of child nodes.
@@ -235,7 +235,7 @@ typedef NS_ENUM(unsigned short, HTMLDocumentPosition)
 
  @param nodes The nodes to append.
  */
-- (void)appendNodes:(NSArray *)nodes;
+- (void)appendNodes:(NSArray<HTMLNode *> *)nodes;
 
 /**
  Inserts a given node before a child node.
diff --git a/Sources/include/HTMLParser.h b/Sources/include/HTMLParser.h
index 18858e8..d5fe596 100644
--- a/Sources/include/HTMLParser.h
+++ b/Sources/include/HTMLParser.h
@@ -24,7 +24,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  An array of errors that occurred during document parsing.
  */
-@property (nonatomic, strong, readonly) NSArray *parseErrors;
+@property (nonatomic, strong, readonly) NSArray<NSString *> *parseErrors;
 
 /**
  The parsed HTML Document.
@@ -67,7 +67,7 @@ NS_ASSUME_NONNULL_BEGIN
 
  @see HTMLElement
  */
-- (NSArray *)parseFragmentWithContextElement:(HTMLElement *)contextElement;
+- (NSArray<HTMLNode *> *)parseFragmentWithContextElement:(HTMLElement *)contextElement;
 
 @end