* src/bin/man/ltlfilt.x: Add a bibliography section.

src/bin/man/ltlfilt.x

@@ -2,5 +2,38 @@
 ltlfilt \- filter files or lists of LTL/PSL formulas
 [DESCRIPTION]
 .\" Add any additional description here
+[BIBLIOGRAPHY]
+.TP
+1.
+Kousha Etessami: A note on a question of Peled and Wilke regarding
+stutter-invariant LTL. Information Processing Letters 75(6): 261-263
+(2000).
+
+Describes the transformation behind the \fB\-\-remove\-x\fR option.
+.TP
+2.
+Christian Dax, Jochen Eisinger, Felix Klaedtke: Mechanizing the
+Powerset Construction for Restricted Classes of
+ω-Automata. Proceedings of ATVA'07.  LNCS 4762.
+
+Describes the checks implemented by the \fB\-\-safety\fR,
+\fB\-\-guarantee\fR, and \fB\-\-obligation\fR options.
+.TP
+3.
+Ivana Černá, Radek Pelánek: Relating Hierarchy of Temporal Properties
+to Model Checking.  Proceedings of MFCS'03.  LNCS 2747.
+
+Describes the syntactic LTL classes matched by the
+\fB\-\-syntactic\-safety\fR, \fB\-\-syntactic\-guarantee\fR,
+\fB\-\-syntactic\-obligation\fR options,
+\fB\-\-syntactic\-persistence\fR, and \fB\-\-syntactic\-recurrence\fR
+options.
+.TP
+4.
+Kousha Etessami, Gerard J. Holzmann: Optimizing Büchi
+Automata. Proceedings of CONCUR'00.  LNCS 1877.
+
+Describe the syntactic LTL classes matched by \fB\-\-eventual\fR, and
+\fB\-\-universal\fR.
 [SEE ALSO]
 .BR randltl (1)