diff --git a/main.bib b/main.bib
index 3ae88a8..c235f82 100644
--- a/main.bib
+++ b/main.bib
@@ -861,10 +861,15 @@
 }
 
 @InBook{Tan2018,
-  title    = {Cluster analysis},
-  pages    = {487--568},
-  subtitle = {Basic concepts and alogrithms},
-  keywords = {compsci},
+  author    = {Tan, Pang-Ning},
+  booktitle = {Introduction to Data Mining},
+  date      = {2005},
+  title     = {Cluster analysis},
+  chapter   = {8},
+  edition   = {1},
+  pages     = {487--568},
+  subtitle  = {Basic concepts and alogrithms},
+  keywords  = {compsci},
 }
 
 @InProceedings{Alur1999,