diff --git a/TODO b/TODO
index 58fad12ea1..e614152f4c 100644
--- a/TODO
+++ b/TODO
@@ -409,3 +409,5 @@ http://www.medical.siemens.com/siemens/en_GLOBAL/rg_marcom_FBAs/files/brochures/
 -----------------------------------------------------------------------
 Other quantization algorithm:
 http://alpng.sourceforge.net/octree.html
+-----------------------------------------------------------------------
+http://www.hitachimed.com/idc/groups/hitachimedical/documents/supportingdocumentpdf/poc_013216.pdf