added two android references

crossrefs.bib

@@ -7100,6 +7100,16 @@
   month =	 may,
 }
 
+@Proceedings{IEEESnP2019,
+  title =	 "IEEE S\&P: 2019 IEEE Symposium on Security and
+                  Privacy",
+  booktitle =	 "IEEE S\&P: 2019 IEEE Symposium on Security and
+                  Privacy",
+  year =	 2019,
+  address =	 "San Francisco, CA, USA",
+  month =	 may,
+}
+
 @Proceedings{IFIPSEC2005,
   title =	 "IFIP SEC 2005: 20th IFIP International Information
                   Security Conference",
@@ -7614,6 +7624,16 @@
   month =	 mar,
 }
 
+@Proceedings{TACAS2013,
+  title =	 "TACAS 2013: Tools and Algorithms for the
+                  Construction and Analysis of Systems",
+  booktitle =	 "TACAS 2013: Tools and Algorithms for the
+                  Construction and Analysis of Systems",
+  year =	 2013,
+  address =	 "Rome, Italy",
+  month =	 mar,
+}
+
 @Proceedings{TACOS2004,
   title =	 "TACoS: International Workshop on Test and Analysis
                   of Component Based Systems",