From f01aec00ea535e81424fb9d68b4401c96b6bdc4d Mon Sep 17 00:00:00 2001
From: Jian-Yang Li <jianyang2li@gmail.com>
Date: Thu, 19 May 2022 17:47:10 -0400
Subject: [PATCH] add ads links to references

---
 sbpy/data/orbit.py | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/sbpy/data/orbit.py b/sbpy/data/orbit.py
index 83ff08dd..35b3cd92 100644
--- a/sbpy/data/orbit.py
+++ b/sbpy/data/orbit.py
@@ -804,15 +804,19 @@ def D_criterion(self, obj, version='sh'):
 
         References
         ----------
-        .. [SH63] Southwarth, R. B., & Hawkins, G. S. 1963, SCoA, 7, 261
+        .. [SH63] `Southwarth, R. B., & Hawkins, G. S. 1963, SCoA, 7, 261
+           <https://ui.adsabs.harvard.edu/abs/1963SCoA....7..261S/abstract>`_
 
-        .. [D81] Drummond, J. D. 1981, Icarus 45, 545
+        .. [D81] `Drummond, J. D. 1981, Icarus 45, 545
+           <https://ui.adsabs.harvard.edu/abs/1981Icar...45..545D/abstract>`_
 
-        .. [J93] Jopek, T. J. 1993, Icarus 106, 603
+        .. [J93] `Jopek, T. J. 1993, Icarus 106, 603
+           <https://ui.adsabs.harvard.edu/abs/1993Icar..106..603J/abstract>`_
 
-        .. [W19] Williams, I. P., Jopek, T. J., Rudawska, R., Tóth, J.,
+        .. [W19] `Williams, I. P., Jopek, T. J., Rudawska, R., Tóth, J.,
            Kornoš, L. 2019, In: Ryabova, G. O., Asher, D. J., Compbell-Brown
            M. D., eds.), Cambridge, UK: Cambridge University Press, 210-234.
+           <https://ui.adsabs.harvard.edu/abs/2019msme.book..210W/abstract>`_
 
 
         Examples