docs: add references to docstrings

docs/references.rst

@@ -0,0 +1,7 @@
+References
+==========
+
+.. [Tankersley2023] Tankersley, Matt (2023). Airborne Geophysical Investigation beneath Antarctica's Ross Ice Shelf. Open Access Te Herenga Waka-Victoria University of Wellington. Thesis. https://doi.org/10.26686/wgtn.24408304
+.. [Uieda2017] Uieda, Leonardo, and Valéria C.F. Barbosa. “Fast Nonlinear Gravity Inversion in Spherical Coordinates with Application to the South American Moho.” Geophysical Journal International 208, no. 1 (January 1, 2017): 162–76. https://doi.org/10.1093/gji/ggw390.
+.. [McCubbine2016] McCubbine, Jack. “Airborne Gravity Across New Zealand - For An Improved Vertical Datum.” Victoria University of Wellington, 2016. http://hdl.handle.net/10063/5264.
+

src/invert4geom/cross_validation.py

@@ -124,6 +124,11 @@ def grav_cv_score(
     float
         a score, represented by the root mean squared error, between the testing gravity
         data and the predicted gravity data.
+
+    References
+    ----------
+    [Uieda2017]_
+
     """
 
     train = training_data.copy()
@@ -317,6 +322,11 @@ def constraints_cv_score(
     float
         a score, represented by the root mean squared error, between the testing gravity
         data and the predicted gravity data.
+
+    References
+    ----------
+    [Uieda2017]_
+
     """
 
     zref: float = kwargs.get("zref")  # type: ignore[assignment]

src/invert4geom/inversion.py

@@ -50,6 +50,10 @@ def grav_column_der(
     NDArray
         array of vertical derivative of gravity at observation point for series of
         prisms
+
+    References
+    ----------
+    [McCubbine2016]_
     """
 
     r = np.sqrt(
@@ -117,6 +121,11 @@ def jacobian_annular(
     -------
     NDArray
         returns a jacobian matrix of shape (number of gravity points, number of prisms)
+
+    References
+    ----------
+    [McCubbine2016]_
+
     """
 
     for i in numba.prange(len(grav_easting)):  # pylint: disable=not-an-iterable