diff --git a/docs/ACKNOWLEDGEMENT.md b/docs/ACKNOWLEDGEMENT.md
index a71e7ceab..ca82c3cbc 100644
--- a/docs/ACKNOWLEDGEMENT.md
+++ b/docs/ACKNOWLEDGEMENT.md
@@ -409,6 +409,16 @@ A. P. Hammersley, H. J. Bernstein and J. D. Westbrook, "Image dictionary (imgCIF
 International Tables for Crystallography Vol. G, 444-458
 [doi:10.1107/97809553602060000746](https://doi.org/10.1107/97809553602060000746).
 
+**d\*TREK SMV** - the SMV reader reads the d\*TREK header vocabulary written by Rigaku's
+CrystalClear (Saturn and R-AXIS detectors: detector and spatial-distortion vectors, detector
+circles, 2theta arm, encoded overflows) from the headers themselves, interpreting the detector
+vectors as dxtbx does for these detectors; no d\*TREK or dxtbx code is used.
+J. W. Pflugrath, "The finer things in X-ray diffraction data collection" (1999), Acta Cryst. D55,
+1718-1725 [doi:10.1107/S090744499900935X](https://doi.org/10.1107/S090744499900935X);
+[dxtbx](https://github.com/cctbx/dxtbx): J. M. Parkhurst, A. S. Brewster, L. Fuentes-Montero,
+D. G. Waterman et al., "dxtbx: the diffraction experiment toolbox" (2014), J. Appl. Cryst. 47,
+1459-1465 [doi:10.1107/S1600576714011996](https://doi.org/10.1107/S1600576714011996).
+
 ## Public diffraction data used for testing
 
 In addition to in-house datasets collected at SLS 2.0, Jungfraujoch is tested against public
diff --git a/reader/SMV.cpp b/reader/SMV.cpp
index 268a59bfb..c497afb36 100644
--- a/reader/SMV.cpp
+++ b/reader/SMV.cpp
@@ -108,6 +108,8 @@ std::vector<std::string> Words(const std::map<std::string, std::string> &kv, con
     return out;
 }
 
+// Following Pflugrath (1999) Acta Cryst. D55, 1718-1725 (d*TREK) and dxtbx, Parkhurst et al. (2014)
+// J. Appl. Cryst. 47, 1459-1465.
 // d*TREK, as Rigaku's CrystalClear writes it for the Saturn and R-AXIS families. Read the way dxtbx's
 // FormatSMVRigakuSaturn reads it: the image directions are <det>DETECTOR_VECTORS combined by
 // <det>SPATIAL_DISTORTION_VECTORS, the point of normal incidence (pixels) and the pixel size (mm) come