Another source for books/sociology/secrecy

diff --git a/books/sociology/secrecy.md b/books/sociology/secrecy.md
index 693106a06e693554ba2d7913587ed3fecb3cff90..6d1043008c033303ac226bae4135bca871b23f13 100644 (file)
--- a/books/sociology/secrecy.md
+++ b/books/sociology/secrecy.md
@@ -2,6 +2,7 @@
 
 By Georg Simmel:
 
+* [Original article](http://doi.org/10.1086/211418).
 * [Full text](https://brocku.ca/MeadProject/Simmel/Simmel_1906.html).
 * [Comments and references](https://en.wikipedia.org/wiki/Sociological_aspects_of_secrecy).