@@ -871,19 +871,14 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
871871def  reindl (surface_tilt , surface_azimuth , dhi , dni , ghi , dni_extra ,
872872           solar_zenith , solar_azimuth ):
873873    r''' 
874-     Determine diffuse irradiance from the sky on a tilted surface using 
875-     Reindl's 1990 model 
876- 
877-     .. math:: 
874+     Determine the diffuse irradiance from the sky on a tilted surface using 
875+     the Reindl (1990) model. 
878876
879-        I_{d} = DHI \left(A R_b + (1 - A) \left(\frac{1 + \cos\beta}{2}\right) 
880-        \left(1 + \sqrt{\frac{I_{hb}}{I_h}} \sin^3(\beta/2)\right) \right) 
881- 
882-     Reindl's 1990 model determines the diffuse irradiance from the sky 
883-     (ground reflected irradiance is not included in this algorithm) on a 
884-     tilted surface using the surface tilt angle, surface azimuth angle, 
877+     The Reindl (1990) model [1]_ [2]_ determines the diffuse irradiance from 
878+     the sky on 
879+     a tilted surface using the surface tilt angle, surface azimuth angle, 
885880    diffuse horizontal irradiance, direct normal irradiance, global 
886-     horizontal irradiance, extraterrestrial irradiance, sun zenith 
881+     horizontal irradiance, extraterrestrial normal  irradiance, sun zenith 
887882    angle, and sun azimuth angle. 
888883
889884    Parameters 
@@ -905,7 +900,7 @@ def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra,
905900        direct normal irradiance. [Wm⁻²] 
906901
907902    ghi: numeric 
908-         Global irradiance. [Wm⁻²] 
903+         Global horizontal  irradiance. [Wm⁻²] 
909904
910905    dni_extra : numeric 
911906        Extraterrestrial normal irradiance. [Wm⁻²] 
@@ -925,23 +920,41 @@ def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra,
925920
926921    Notes 
927922    ----- 
928-     The poa_sky_diffuse calculation is generated from the Loutzenhiser et al. 
929-     (2007) paper, equation 8. Note that I have removed the beam and ground 
930-     reflectance portion of the equation and this generates ONLY the diffuse 
931-     radiation from the sky and circumsolar, so the form of the equation 
932-     varies slightly from equation 8. 
923+     The Reindl (1990) model  for the sky diffuse irradiance, 
924+     :math:`I_d`, is as follows: 
925+ 
926+     .. math:: 
927+ 
928+        I_{d} = DHI \left(A \cdot R_b + (1 - A) 
929+                          \left(\frac{1 + \cos\beta}{2}\right) 
930+        \left(1 + \sqrt{\frac{BHI}{GHI}} \sin^3(\beta/2)\right) \right). 
931+ 
932+     :math:`DHI`, :math:`BHI`, and :math:`GHI` are the diffuse horizontal, beam 
933+     (direct) horizontal and global horizontal irradiances, respectively. 
934+     :math:`A` is the anisotropy index, which is the ratio of the direct normal 
935+     irradiance to the direct extraterrestrial irradiation, :math:`R_b` is the 
936+     projection ratio, which is defined as the ratio of the cosine of the angle 
937+     of incidence (AOI) to the cosine of the zenith angle, and :math:`\beta` 
938+     is the tilt angle of the array. 
939+ 
940+     Implementation is based on Loutzenhiser et al. 
941+     (2007) [3]_, Equation 8. The beam and ground reflectance portion of the 
942+     equation have been removed, therefore the model described here generates 
943+     ONLY the diffuse radiation from the sky and circumsolar, so the form of the 
944+     equation varies slightly from Equation 8 in [3]_. 
933945
934946    References 
935947    ---------- 
936-     .. [1] Loutzenhiser P.G. et. al. "Empirical validation of models to 
937-        compute solar irradiance on inclined surfaces for building energy 
938-        simulation" 2007, Solar Energy vol. 81. pp. 254-267 
939- 
940-     .. [2] Reindl, D.T., Beckmann, W.A., Duffie, J.A., 1990a. Diffuse 
948+     .. [1] Reindl, D. T., Beckmann, W. A., Duffie, J. A., 1990a. Diffuse 
941949       fraction correlations. Solar Energy 45(1), 1-7. 
942- 
943-     .. [3 ] Reindl, D.T., Beckmann, W.A., Duffie, J.A., 1990b. Evaluation of 
950+        :doi:`10.1016/0038-092X(90)90060-P` 
951+     .. [2 ] Reindl, D.  T., Beckmann, W.  A., Duffie, J.  A., 1990b. Evaluation of 
944952       hourly tilted surface radiation models. Solar Energy 45(1), 9-17. 
953+        :doi:`10.1016/0038-092X(90)90061-G` 
954+     .. [3] Loutzenhiser P. G. et. al., 2007. Empirical validation of models to 
955+        compute solar irradiance on inclined surfaces for building energy 
956+        simulation. Solar Energy 81(2), 254-267 
957+        :doi:`10.1016/j.solener.2006.03.009` 
945958    ''' 
946959
947960    cos_tt  =  aoi_projection (surface_tilt , surface_azimuth ,
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