CRM-13904 - add links to formula used

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* CRM-13904: Improve proximity query accuracy
  http://issues.civicrm.org/jira/browse/CRM-13904

diff --git a/CRM/Contact/BAO/ProximityQuery.php b/CRM/Contact/BAO/ProximityQuery.php
index 8f1295ff1de222f7d2608ad5c3ec883e68db9e89..9008e6f4e8e9429e901593c6426233bce8ca315e 100644 (file)
--- a/CRM/Contact/BAO/ProximityQuery.php
+++ b/CRM/Contact/BAO/ProximityQuery.php
@@ -36,6 +36,11 @@ class CRM_Contact_BAO_ProximityQuery {
 
   /**
    * Trigonometry for calculating geographical distances.
+   *
+   * Modification made in: CRM-13904
+   * http://en.wikipedia.org/wiki/Great-circle_distance
+   * http://www.movable-type.co.uk/scripts/latlong.html
+   *
    * All function arguments and return values measure distances in metres
    * and angles in degrees.  The ellipsoid model is from the WGS-84 datum.
    * Ka-Ping Yee, 2003-08-11