I believe I added this because it has information on the history of intuitionism

math.bib

@@ -252,6 +252,15 @@
 	author = {Troelstra, Anne Sjerp}
 }
 
+@Book{vanheijenoort1967frege,
+	publisher = {Harvard University Press},
+	volume = {9},
+	year = {1967},
+	subtitle = {a source book in mathematical logic, 1879--1931},
+	title = {From Frege to Gödel},
+	author = {Van Heijenoort, Jean}
+}
+
 @Comment{
 Local Variables:
 bibtex-dialect: biblatex