update reference

Author: staroperator

Mathlib/ModelTheory/Arithmetic/Presburger/Definability.lean

@@ -46,9 +46,10 @@ definable.
 
 ## References
 
-- Seymour Ginsburg and Edwin H. Spanier, Bounded Algol-Like Languages.
-- Seymour Ginsburg and Edwin H. Spanier, Semigroups, Presburger Formulas, and Languages.
-- Samuel Eilenberg and M. P. Schützenberger, Rational Sets in Commutative Monoids.
+* [Seymour Ginsburg and Edwin H. Spanier, *Bounded ALGOL-Like Languages*][ginsburg1964]
+* [Seymour Ginsburg and Edwin H. Spanier, *Semigroups, Presburger Formulas, and Languages*][
+  ginsburg1966]
+* [Samuel Eilenberg and M. P. Schützenberger, *Rational Sets in Commutative Monoids*][eilenberg1969]
 -/
 
 universe u v w

docs/references.bib

@@ -2082,6 +2082,17 @@ @Article{         ginsburg1964
   publisher     = {JSTOR}
 }
 
+@Article{         ginsburg1966,
+  title         = {Semigroups, Presburger formulas, and languages},
+  author        = {Ginsburg, Seymour and Spanier, Edwin},
+  journal       = {Pacific journal of Mathematics},
+  volume        = {16},
+  number        = {2},
+  pages         = {285--296},
+  year          = {1966},
+  publisher     = {Mathematical Sciences Publishers}
+}
+
 @Book{            giraud1971,
   author        = {Giraud, Jean},
   title         = {Cohomologie non ab\'elienne},