Merge pull request #44 from softdevteam/ammann78error

Add Ammann '78 paper.

Author: ptersilie

softdev.bib

@@ -2164,3 +2164,13 @@ @book{holub90compilerdesign
     year = 1990,
     publisher = "Prentice-Hall"
 }
+
+@techreport{ammann78error,
+    author = "Urs Ammann",
+    title = "Error recovery in recursive descent parsers",
+    number = "136031",
+    institution = "ETH Zürich",
+    year = "1978",
+    month = May,
+    doi = "10.3929/ethz-a-000136031"
+}