Index: doc/bibliography/cfa.bib
===================================================================
--- doc/bibliography/cfa.bib	(revision 7e17503b8d54e1bbc54d23afb27cb8b6f5859434)
+++ doc/bibliography/cfa.bib	(revision daf9671439895f6d3bdd15ca16d77fa736b00a4c)
@@ -3035,4 +3035,14 @@
     year	= 1992,
     pages	= {T1-53},
+}
+
+@manual{GMP,
+    keywords	= {GMP arbitrary-precision library},
+    contributer	= {pabuhr@plg},
+    title	= {{GNU} Multiple Precision Arithmetic Library},
+    author	= {GMP},
+    organization= {GNU},
+    year	= 2016,
+    note	= {\href{https://gmplib.org}{https://\-gmplib.org}},
 }