diff --git a/poppler/Annot.cc b/poppler/Annot.cc
index 3bc776e..a061a1b 100644
--- a/poppler/Annot.cc
+++ b/poppler/Annot.cc
@@ -1997,8 +1997,7 @@
   if (irtObj.isRef()) {
     inReplyTo = irtObj.getRef();
   } else {
-    inReplyTo.num = 0;
-    inReplyTo.gen = 0;
+    inReplyTo = Ref::INVALID();
   }
 
   obj1 = dict->lookup("Subj");
diff --git a/poppler/Annot.h b/poppler/Annot.h
index 9f6c9fb..3a93794 100644
--- a/poppler/Annot.h
+++ b/poppler/Annot.h
@@ -821,6 +821,7 @@
   double getOpacity() const { return opacity; }
   // getRC
   const GooString *getDate() const { return date.get(); }
+  bool isInReplyTo() const { return inReplyTo != Ref::INVALID(); }
   int getInReplyToID() const { return inReplyTo.num; }
   const GooString *getSubject() const { return subject.get(); }
   AnnotMarkupReplyType getReplyTo() const { return replyTo; }
diff --git a/poppler/Array.cc b/poppler/Array.cc
index cc7dd0c..a6cf4bc 100644
--- a/poppler/Array.cc
+++ b/poppler/Array.cc
@@ -80,13 +80,13 @@
 Object Array::get(int i, Ref *returnRef, int recursion) const
 {
   if (i < 0 || std::size_t(i) >= elems.size()) {
-    *returnRef = { 0, 0 };
+    *returnRef = Ref::INVALID();
     return Object(objNull);
   }
   if (elems[i].getType() == objRef) {
     *returnRef = elems[i].getRef();
   } else {
-    *returnRef = { 0, 0 };
+    *returnRef = Ref::INVALID();
   }
   return elems[i].fetch(xref, recursion);
 }
diff --git a/poppler/Array.h b/poppler/Array.h
index 1d03cbc..be1123c 100644
--- a/poppler/Array.h
+++ b/poppler/Array.h
@@ -68,6 +68,7 @@
 
   // Accessors.
   Object get(int i, int recursion = 0) const;
+  // Same as above but if the returned object is a fetched Ref returns such Ref in returnRef, otherwise returnRef is Ref::INVALID()
   Object get(int i, Ref *returnRef, int recursion = 0) const;
   const Object &getNF(int i) const;
   bool getString(int i, GooString *string) const;
diff --git a/poppler/Catalog.cc b/poppler/Catalog.cc
index 905954e..d01e8fc 100644
--- a/poppler/Catalog.cc
+++ b/poppler/Catalog.cc
@@ -502,7 +502,7 @@
   embeddedFilesObj.dictSet("Names", Object(embeddedFilesNamesArray));
   namesDict->set("EmbeddedFiles", Object(embeddedFilesRef));
 
-  if (namesObjRef.num != 0) {
+  if (namesObjRef != Ref::INVALID()) {
     xref->setModifiedObject(&namesObj, namesObjRef);
   } else {
     xref->setModifiedObject(&catDict, { xref->getRootNum(), xref->getRootGen() });
diff --git a/poppler/Dict.cc b/poppler/Dict.cc
index f1d6c6e..17c2f98 100644
--- a/poppler/Dict.cc
+++ b/poppler/Dict.cc
@@ -173,11 +173,11 @@
     if (entry->second.getType() == objRef) {
       *returnRef = entry->second.getRef();
     } else {
-      *returnRef = { 0, 0 };
+      *returnRef = Ref::INVALID();
     }
     return entry->second.fetch(xref, recursion);
   }
-  *returnRef = { 0, 0 };
+  *returnRef = Ref::INVALID();
   return Object(objNull);
 }
 
diff --git a/poppler/Dict.h b/poppler/Dict.h
index 13da482..6c1424a 100644
--- a/poppler/Dict.h
+++ b/poppler/Dict.h
@@ -76,6 +76,7 @@
   // Look up an entry and return the value.  Returns a null object
   // if <key> is not in the dictionary.
   Object lookup(const char *key, int recursion = 0) const;
+  // Same as above but if the returned object is a fetched Ref returns such Ref in returnRef, otherwise returnRef is Ref::INVALID()
   Object lookup(const char *key, Ref *returnRef, int recursion = 0) const;
   const Object &lookupNF(const char *key) const;
   bool lookupInt(const char *key, const char *alt_key, int *value) const;
diff --git a/poppler/Function.cc b/poppler/Function.cc
index 873c2c0..e7973e2 100644
--- a/poppler/Function.cc
+++ b/poppler/Function.cc
@@ -692,7 +692,7 @@
     std::set<int> usedParentsAux = *usedParents;
     Ref ref;
     Object obj2 = obj1.getArray()->get(i, &ref);
-    if (ref.num != 0) {
+    if (ref != Ref::INVALID()) {
       if (usedParentsAux.find(ref.num) == usedParentsAux.end()) {
         usedParentsAux.insert(ref.num);
       } else {
diff --git a/poppler/GfxFont.cc b/poppler/GfxFont.cc
index db6f0b8..c74b4b0 100644
--- a/poppler/GfxFont.cc
+++ b/poppler/GfxFont.cc
@@ -290,7 +290,7 @@
   bool isType0, err;
 
   t = fontUnknownType;
-  embID->num = embID->gen = -1;
+  *embID = Ref::INVALID();
   err = false;
 
   Object subtype = fontDict->lookup("Subtype");
@@ -348,7 +348,7 @@
 	err = true;
       }
     }
-    if (embID->num == -1 && (obj3 = fontDesc.dictLookupNF("FontFile2").copy(), obj3.isRef())) {
+    if (*embID == Ref::INVALID() && (obj3 = fontDesc.dictLookupNF("FontFile2").copy(), obj3.isRef())) {
       *embID = obj3.getRef();
       if (isType0) {
 	expectedType = fontCIDType2;
@@ -356,7 +356,7 @@
 	err = true;
       }
     }
-    if (embID->num == -1 && (obj3 = fontDesc.dictLookupNF("FontFile3").copy(), obj3.isRef())) {
+    if (*embID == Ref::INVALID() && (obj3 = fontDesc.dictLookupNF("FontFile3").copy(), obj3.isRef())) {
       *embID = obj3.getRef();
       Object obj4 = obj3.fetch(xref);
       if (obj4.isStream()) {
@@ -406,7 +406,7 @@
   }
 
   t = fontUnknownType;
-  if (embID->num >= 0) {
+  if (*embID != Ref::INVALID()) {
     Object obj3(*embID);
     Object obj4 = obj3.fetch(xref);
     if (obj4.isStream()) {
diff --git a/poppler/GfxFont.h b/poppler/GfxFont.h
index 740a29c..54ab128 100644
--- a/poppler/GfxFont.h
+++ b/poppler/GfxFont.h
@@ -213,7 +213,7 @@
   // Get embedded font ID, i.e., a ref for the font file stream.
   // Returns false if there is no embedded font.
   bool getEmbeddedFontID(Ref *embID) const
-    { *embID = embFontID; return embFontID.num >= 0; }
+    { *embID = embFontID; return embFontID != Ref::INVALID(); }
 
   // Invalidate an embedded font
   // Returns false if there is no embedded font.
diff --git a/poppler/GfxState.cc b/poppler/GfxState.cc
index e3417e0..557ce46 100644
--- a/poppler/GfxState.cc
+++ b/poppler/GfxState.cc
@@ -1815,7 +1815,6 @@
 
 GfxColorSpace *GfxICCBasedColorSpace::parse(Array *arr, OutputDev *out, GfxState *state, int recursion) {
   GfxICCBasedColorSpace *cs;
-  Ref iccProfileStreamA;
   int nCompsA;
   GfxColorSpace *altA;
   Dict *dict;
@@ -1827,15 +1826,10 @@
     return nullptr;
   }
   const Object &obj1Ref = arr->getNF(1);
-  if (obj1Ref.isRef()) {
-    iccProfileStreamA = obj1Ref.getRef();
-  } else {
-    iccProfileStreamA.num = 0;
-    iccProfileStreamA.gen = 0;
-  }
+  const Ref iccProfileStreamA = obj1Ref.isRef() ? obj1Ref.getRef() : Ref::INVALID();
 #ifdef USE_CMS
   // check cache
-  if (out && iccProfileStreamA.num > 0) {
+  if (out && iccProfileStreamA != Ref::INVALID()) {
     if (auto *item = out->getIccColorSpaceCache()->lookup(iccProfileStreamA)) {
       cs = static_cast<GfxICCBasedColorSpace*>(item->copy());
       int transformIntent = cs->getIntent();
@@ -1976,7 +1970,7 @@
     cmsCloseProfile(hp);
   }
   // put this colorSpace into cache
-  if (out && iccProfileStreamA.num > 0) {
+  if (out && iccProfileStreamA != Ref::INVALID()) {
     out->getIccColorSpaceCache()->put(iccProfileStreamA, static_cast<GfxICCBasedColorSpace*>(cs->copy()));
   }
 #endif
diff --git a/poppler/Link.h b/poppler/Link.h
index 08949ea..c1079bd 100644
--- a/poppler/Link.h
+++ b/poppler/Link.h
@@ -310,13 +310,13 @@
   LinkMovie(const Object *obj);
   ~LinkMovie();
 
-  bool isOk() const override { return annotRef.num >= 0 || annotTitle != nullptr; }
+  bool isOk() const override { return hasAnnotRef() || hasAnnotTitle(); }
   LinkActionKind getKind() const override { return actionMovie; }
 
   // a movie action stores either an indirect reference to a movie annotation
   // or the movie annotation title
 
-  bool hasAnnotRef() const { return annotRef.num >= 0; }
+  bool hasAnnotRef() const { return annotRef != Ref::INVALID(); }
   bool hasAnnotTitle() const { return annotTitle != nullptr; }
   const Ref *getAnnotRef() const { return &annotRef; }
   const GooString *getAnnotTitle() const { return annotTitle; }
diff --git a/qt5/src/poppler-annotation-private.h b/qt5/src/poppler-annotation-private.h
index b0072af..937edad 100644
--- a/qt5/src/poppler-annotation-private.h
+++ b/qt5/src/poppler-annotation-private.h
@@ -97,7 +97,7 @@
         AnnotPath * toAnnotPath(const QLinkedList<QPointF> &l) const;
 
         /* Scan page for annotations, parentId=0 searches for root annotations, subtypes empty means all subtypes */
-        static QList<Annotation*> findAnnotations(::Page *pdfPage, DocumentData *doc, const QSet<Annotation::SubType> &subtypes, int parentId = 0);
+        static QList<Annotation*> findAnnotations(::Page *pdfPage, DocumentData *doc, const QSet<Annotation::SubType> &subtypes, int parentId = -1);
 
         /* Add given annotation to given page */
         static void addAnnotationToPage(::Page *pdfPage, DocumentData *doc, const Annotation * ann);
diff --git a/qt5/src/poppler-annotation.cc b/qt5/src/poppler-annotation.cc
index 80a8589..207d6ca 100644
--- a/qt5/src/poppler-annotation.cc
+++ b/qt5/src/poppler-annotation.cc
@@ -1,5 +1,5 @@
 /* poppler-annotation.cc: qt interface to poppler
- * Copyright (C) 2006, 2009, 2012-2015, 2018 Albert Astals Cid <aacid@kde.org>
+ * Copyright (C) 2006, 2009, 2012-2015, 2018, 2019 Albert Astals Cid <aacid@kde.org>
  * Copyright (C) 2006, 2008, 2010 Pino Toscano <pino@kde.org>
  * Copyright (C) 2012, Guillermo A. Amaral B. <gamaral@kde.org>
  * Copyright (C) 2012-2014 Fabio D'Urso <fabiodurso@hotmail.it>
@@ -1741,7 +1741,7 @@
 
     const AnnotMarkup *markupann = dynamic_cast<const AnnotMarkup*>(d->pdfAnnot);
 
-    if (markupann && markupann->getInReplyToID() != 0)
+    if (markupann && markupann->isInReplyTo())
     {
         switch (markupann->getReplyTo())
         {
@@ -1764,7 +1764,7 @@
 
     const AnnotText *textann = dynamic_cast<const AnnotText*>(d->pdfAnnot);
 
-    if (textann && textann->getInReplyToID() != 0)
+    if (textann && textann->isInReplyTo())
     {
         switch (textann->getState())
         {