diff --git a/pytransform3d/rotations/_conversions.py b/pytransform3d/rotations/_conversions.py
index 4fa14c7d0..14bbc7e44 100644
--- a/pytransform3d/rotations/_conversions.py
+++ b/pytransform3d/rotations/_conversions.py
@@ -965,8 +965,10 @@ def _general_intrinsic_euler_from_active_matrix(
 
     References
     ----------
-    Shuster, Markley: General Formula for Extracting the Euler Angles,
-    https://arc.aiaa.org/doi/abs/10.2514/1.16622
+    .. [1] Shuster, M. D., Markley, F. L. (2006).
+       General Formula for Extracting the Euler Angles.
+       Journal of Guidance, Control, and Dynamics, 29(1), pp 2015-221,
+       doi: 10.2514/1.16622. https://arc.aiaa.org/doi/abs/10.2514/1.16622
     """
     D = check_matrix(R, strict_check=strict_check)
 
@@ -1572,8 +1574,10 @@ def euler_from_matrix(R, i, j, k, extrinsic, strict_check=True):
 
     References
     ----------
-    Shuster, Markley: General Formula for Extracting the Euler Angles,
-    https://arc.aiaa.org/doi/abs/10.2514/1.16622
+    .. [1] Shuster, M. D., Markley, F. L. (2006).
+       General Formula for Extracting the Euler Angles.
+       Journal of Guidance, Control, and Dynamics, 29(1), pp 2015-221,
+       doi: 10.2514/1.16622. https://arc.aiaa.org/doi/abs/10.2514/1.16622
     """
     check_axis_index("i", i)
     check_axis_index("j", j)
@@ -1628,9 +1632,9 @@ def euler_from_quaternion(q, i, j, k, extrinsic):
 
     References
     ----------
-    Bernardes, Evandro; Viollet, Stephane: Quaternion to Euler angles
-    conversion: A direct, general and computationally efficient method,
-    https://doi.org/10.1371/journal.pone.0276302
+    .. [1] Bernardes, E., Viollet, S. (2022). Quaternion to Euler angles
+       conversion: A direct, general and computationally efficient method.
+       PLOS ONE, 17(11), doi: 10.1371/journal.pone.0276302.
     """
     q = check_quaternion(q)
 
diff --git a/pytransform3d/transformations/_dual_quaternion_operations.py b/pytransform3d/transformations/_dual_quaternion_operations.py
index c1a04acdb..8b5bbd43b 100644
--- a/pytransform3d/transformations/_dual_quaternion_operations.py
+++ b/pytransform3d/transformations/_dual_quaternion_operations.py
@@ -144,9 +144,10 @@ def dual_quaternion_sclerp(start, end, t):
 
     References
     ----------
-    Kavan, Collins, O'Sullivan, Zara: Dual Quaternions for Rigid Transformation
-    Blending (2006), Technical report, Trinity College Dublin,
-    https://users.cs.utah.edu/~ladislav/kavan06dual/kavan06dual.pdf
+    .. [1] Kavan, L., Collins, S., O'Sullivan, C., Zara, J. (2006).
+       Dual Quaternions for Rigid Transformation Blending, Technical report,
+       Trinity College Dublin,
+       https://users.cs.utah.edu/~ladislav/kavan06dual/kavan06dual.pdf
 
     See Also
     --------
diff --git a/pytransform3d/transformations/_jacobians.py b/pytransform3d/transformations/_jacobians.py
index 55b9433d5..4bdff6726 100644
--- a/pytransform3d/transformations/_jacobians.py
+++ b/pytransform3d/transformations/_jacobians.py
@@ -47,9 +47,10 @@ def left_jacobian_SE3(Stheta):
 
     References
     ----------
-    Barfoot, Furgale: Associating Uncertainty With Three-Dimensional Poses for
-    Use in Estimation Problems,
-    http://ncfrn.mcgill.ca/members/pubs/barfoot_tro14.pdf
+    .. [1] Barfoot, T. D., Furgale, P. T. (2014).
+       Associating Uncertainty With Three-Dimensional Poses for Use in
+       Estimation Problems. IEEE Transactions on Robotics, 30(3), pp. 679-693,
+       doi: 10.1109/TRO.2014.2298059.
     """
     Stheta = check_exponential_coordinates(Stheta)