Fixes to geodesic documention:

* replace SVG figure by PNG version,
* rewrite maths using :math:,
* put references in the main reference section,
* reformat references for consistency,
* put references in alphabetical order,
* use USGS URL for Snyder (1987).

2 files changed, 179 insertions, 142 deletions

diff --git a/docs/source/geodesic.rst b/docs/source/geodesic.rst
index 29327ae8..d54212ca 100644
--- a/docs/source/geodesic.rst
+++ b/docs/source/geodesic.rst
@@ -10,53 +10,52 @@ Geodesic calculations
 Introduction
 ------------
 
-Consider a ellipsoid of revolution with equatorial radius *a*, polar
-semi-axis *b*, and flattening *f* = (*a* − *b*)/*a* .  Points on
-the surface of the ellipsoid are characterized by their latitude φ
-and longitude λ.  (Note that latitude here means the
+Consider a ellipsoid of revolution with equatorial radius :math:`a`, polar
+semi-axis :math:`b`, and flattening :math:`f=(a−b)/a`.  Points on
+the surface of the ellipsoid are characterized by their latitude :math:`\phi`
+and longitude :math:`\lambda`.  (Note that latitude here means the
 *geographical latitude*, the angle between the normal to the ellipsoid
 and the equatorial plane).
 
 The shortest path between two points on the ellipsoid at
-(φ\ :sub:`1`, λ\ :sub:`1`) and (φ\ :sub:`2`, λ\ :sub:`2`)
+:math:`(\phi_1,\lambda_1)` and :math:`(\phi_2,\lambda_2)`
 is called the geodesic.  Its length is
-*s*\ :sub:`12` and the geodesic from point 1 to point 2 has forward
-azimuths α\ :sub:`1` and α\ :sub:`2` at the two end
-points.  In this figure, we have λ\ :sub:`12` =
-λ\ :sub:`2` − λ\ :sub:`1`.
+:math:`s_{12}` and the geodesic from point 1 to point 2 has forward
+azimuths :math:`\alpha_1` and :math:`\alpha_2` at the two end
+points.  In this figure, we have :math:`\lambda_{12}=\lambda_2-\lambda_1`.
 
     .. raw:: html
 
        <center>
-         <img src="https://upload.wikimedia.org/wikipedia/commons/c/cb/Geodesic_problem_on_an_ellipsoid.svg"
+         <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Geodesic_problem_on_an_ellipsoid.svg/320px-Geodesic_problem_on_an_ellipsoid.svg.png"
               alt="Figure from wikipedia"
-              width="250">
+              width="320">
        </center>
 
 A geodesic can be extended indefinitely by requiring that any
 sufficiently small segment is a shortest path; geodesics are also the
 straightest curves on the surface.
 
-Solution of geodesic programs
+Solution of geodesic problems
 -----------------------------
 
 Traditionally two geodesic problems are considered:
 
-* the direct problem — given φ\ :sub:`1`,
-  λ\ :sub:`1`, α\ :sub:`1`, *s*\ :sub:`12`,
-  determine φ\ :sub:`2`, λ\ :sub:`2`, and
-  α\ :sub:`2`.
+* the direct problem — given :math:`\phi_1`,
+  :math:`\lambda_1`, :math:`\alpha_1`, :math:`s_{12}`,
+  determine :math:`\phi_2`, :math:`\lambda_2`, :math:`\alpha_2`.
 
-* the inverse problem — given φ\ :sub:`1`,
-  λ\ :sub:`1`, φ\ :sub:`2`, λ\ :sub:`2`,
-  determine *s*\ :sub:`12`, α\ :sub:`1`, and
-  α\ :sub:`2`.
+* the inverse problem — given  :math:`\phi_1`,
+  :math:`\lambda_1`,  :math:`\phi_2`, :math:`\lambda_2`,
+  determine :math:`s_{12}`, :math:`\alpha_1`,
+  :math:`\alpha_2`.
 
 PROJ incorporates `C library for Geodesics
 <https://geographiclib.sourceforge.io/1.49/C/>`_ from `GeographicLib
 <https://geographiclib.sourceforge.io>`_.  This library provides
 routines to solve the direct and inverse geodesic problems.  Full double
-precision accuracy is maintained provided that −0.02 < *f* < 0.02.  Refer
+precision accuracy is maintained provided that
+:math:`\lvert f\rvert<\frac1{50}`.  Refer
 to the
 
     `application programming interface
@@ -70,9 +69,9 @@ rest of PROJ:
 
 * angles (latitudes, longitudes, and azimuths) are in degrees (instead
   of in radians);
-* the shape of ellipsoid is specified by the flattening *f*; this can
-  be negative to denote a prolate ellipsoid; setting *f* = 0 corresponds
-  to a sphere in which case the geodesic becomes a great circle.
+* the shape of ellipsoid is specified by the flattening :math:`f`; this can
+  be negative to denote a prolate ellipsoid; setting :math:`f=0` corresponds
+  to a sphere, in which case the geodesic becomes a great circle.
 
 PROJ also includes a command line tool, :ref:`geod`\ (1), for performing
 simple geodesic calculations.
@@ -82,47 +81,41 @@ Additional properties
 
 The routines also calculate several other quantities of interest
 
-* *S*\ :sub:`12` is the area between the geodesic from point 1 to
+* :math:`S_{12}` is the area between the geodesic from point 1 to
   point 2 and the equator; i.e., it is the area, measured
   counter-clockwise, of the quadrilateral with corners
-  (φ\ :sub:`1`,λ\ :sub:`1`), (0,λ\ :sub:`1`),
-  (0,λ\ :sub:`2`), and
-  (φ\ :sub:`2`,λ\ :sub:`2`).  It is given in
+  :math:`(\phi_1,\lambda_1)`, :math:`(0,\lambda_1)`,
+  :math:`(0,\lambda_2)`, and
+  :math:`(\phi_2,\lambda_2)`.  It is given in
   meters\ :sup:`2`.
-* *m*\ :sub:`12`, the reduced length of the geodesic is defined such
-  that if the initial azimuth is perturbed by *d*\ α\ :sub:`1`
-  (radians) then the second point is displaced by *m*\ :sub:`12`
-  *d*\ α\ :sub:`1` in the direction perpendicular to the
-  geodesic.  *m*\ :sub:`12` is given in meters.  On a curved surface
-  the reduced length obeys a symmetry relation, *m*\ :sub:`12` +
-  *m*\ :sub:`21` = 0.  On a flat surface, we have *m*\ :sub:`12` =
-  *s*\ :sub:`12`.
-* *M*\ :sub:`12` and *M*\ :sub:`21` are geodesic scales.  If two
+* :math:`m_{12}`, the reduced length of the geodesic is defined such
+  that if the initial azimuth is perturbed by :math:`d\alpha_1`
+  (radians) then the second point is displaced by :math:`m_{12}\,d\alpha_1`
+  in the direction perpendicular to the
+  geodesic.  :math:`m_{12}` is given in meters.  On a curved surface
+  the reduced length obeys a symmetry relation, :math:`m_{12}+m_{21}=0`.
+  On a flat surface, we have :math:`m_{12}=s_{12}`.
+* :math:`M_{12}` and :math:`M_{21}` are geodesic scales.  If two
   geodesics are parallel at point 1 and separated by a small distance
-  *dt*, then they are separated by a distance *M*\ :sub:`12` *dt* at
-  point 2.  *M*\ :sub:`21` is defined similarly (with the geodesics
-  being parallel to one another at point 2).  *M*\ :sub:`12` and
-  *M*\ :sub:`21` are dimensionless quantities.  On a flat surface,
-  we have *M*\ :sub:`12` = *M*\ :sub:`21` = 1.
-* σ\ :sub:`12` is the arc length on the auxiliary sphere.
+  :\math`dt`, then they are separated by a distance :math:`M_{12}\,dt` at
+  point 2.  :math:`M_{21}` is defined similarly (with the geodesics
+  being parallel to one another at point 2).  :math:`M_{12}` and
+  :math:`M_{21}` are dimensionless quantities.  On a flat surface,
+  we have :math:`M_{12}=M_{21}=1`.
+* :math:`\sigma_{12}` is the arc length on the auxiliary sphere.
   This is a construct for converting the problem to one in spherical
   trigonometry.  The spherical arc length from one equator crossing to
-  the next is always 180°.
+  the next is always :math:`180^\circ`.
 
 If points 1, 2, and 3 lie on a single geodesic, then the following
 addition rules hold:
 
-* *s*\ :sub:`13` = *s*\ :sub:`12` + *s*\ :sub:`23`
-* σ\ :sub:`13` = σ\ :sub:`12` + σ\ :sub:`23`
-* *S*\ :sub:`13` = *S*\ :sub:`12` + *S*\ :sub:`23`
-* *m*\ :sub:`13` = *m*\ :sub:`12`\ *M*\ :sub:`23` +
-  *m*\ :sub:`23`\ *M*\ :sub:`21`
-* *M*\ :sub:`13` = *M*\ :sub:`12`\ *M*\ :sub:`23` −
-  (1 − *M*\ :sub:`12`\ *M*\ :sub:`21`)
-  *m*\ :sub:`23`/*m*\ :sub:`12`
-* *M*\ :sub:`31` = *M*\ :sub:`32`\ *M*\ :sub:`21` −
-  (1 − *M*\ :sub:`23`\ *M*\ :sub:`32`)
-  *m*\ :sub:`12`/*m*\ :sub:`23`
+* :math:`s_{13}=s_{12}+s_{23}`,
+* :math:`\sigma_{13}=\sigma_{12}+\sigma_{23}`,
+* :math:`S_{13}=S_{12}+S_{23}`,
+* :math:`m_{13}=m_{12}M_{23}+m_{23}M_{21}`,
+* :math:`M_{13}=M_{12}M_{23}-(1-M_{12}M_{21})m_{23}/m_{12}`,
+* :math:`M_{31}=M_{32}M_{21}-(1-M_{23}M_{32})m_{12}/m_{23}`.
 
 Multiple shortest geodesics
 ---------------------------
@@ -132,42 +125,41 @@ The shortest distance found by solving the inverse problem is
 multiple azimuths which yield the same shortest distance.  Here is a
 catalog of those cases:
 
-* φ\ :sub:`1` = −φ\ :sub:`2` (with neither point at
-  a pole).  If α\ :sub:`1` = α\ :sub:`2`, the geodesic
+* :math:`\phi_1=-\phi_2` (with neither point at
+  a pole).  If :math:`\alpha_1=\alpha_2`, the geodesic
   is unique.  Otherwise there are two geodesics and the second one is
   obtained by setting
-  [α\ :sub:`1`,α\ :sub:`2`] ←  [α\ :sub:`2`,α\ :sub:`1`],
-  [*M*\ :sub:`12`,\ *M*\ :sub:`21`] ← [*M*\ :sub:`21`,\ *M*\ :sub:`12`],
-  *S*\ :sub:`12` ← −\ *S*\ :sub:`12`.
-  (This occurs when the longitude difference is near ±180° for oblate
-  ellipsoids.)
-* λ\ :sub:`2` = λ\ :sub:`1` ± 180° (with
-  neither point at a pole).  If α\ :sub:`1` = 0° or
-  ±180°, the geodesic is unique.  Otherwise there are two
+  :math:`[\alpha_1,\alpha_2]\leftarrow[\alpha_2,\alpha_1]`,
+  :math:`[M_{12},M_{21}]\leftarrow[M_{21},M_{12}]`,
+  :math:`S_{12}\leftarrow-S_{12}`.
+  (This occurs when the longitude difference is near :math:`\pm180^\circ`
+  for oblate ellipsoids.)
+* :math:`\lambda_2=\lambda_1\pm180^\circ` (with
+  neither point at a pole).  If :math:`\alpha_1=0^\circ` or
+  :math:`\pm180^\circ`, the geodesic is unique.  Otherwise there are two
   geodesics and the second one is obtained by setting
-  [α\ :sub:`1`,α\ :sub:`2`] ← [−α\ :sub:`1`,−α\ :sub:`2`],
-  *S*\ :sub:`12` ← −\ *S*\ :sub:`12`.  (This occurs when
-  φ\ :sub:`2` is near −φ\ :sub:`1` for prolate
+  :math:`[\alpha_1,\alpha_2]\leftarrow[-\alpha_1,-\alpha_2]`,
+  :math:`S_{12}\leftarrow-S_{12}`.  (This occurs when
+  :math:`\phi_2` is near :math:`-\phi_1` for prolate
   ellipsoids.)
 * Points 1 and 2 at opposite poles.  There are infinitely many
   geodesics which can be generated by setting
-  [α\ :sub:`1`,α\ :sub:`2`] ←
-  [α\ :sub:`1`,α\ :sub:`2`] + [δ,−δ], for arbitrary δ.
+  :math:`[\alpha_1,\alpha_2]\leftarrow[\alpha_1,\alpha_2]+[\delta,-\delta]`,
+  for arbitrary :math:`\delta`.
   (For spheres, this prescription applies when points 1 and 2 are
   antipodal.)
-* *s*\ :sub:`12` = 0 (coincident points).  There are infinitely many
+* :math:`s_{12}=0` (coincident points).  There are infinitely many
   geodesics which can be generated by setting
-  [α\ :sub:`1`,α\ :sub:`2`]_←
-  [α\ :sub:`1`,α\ :sub:`2`]_+ [δ,δ], for
-  arbitrary δ.
+  :math:`[\alpha_1,\alpha_2]\leftarrow[\alpha_1,\alpha_2]+[\delta,\delta]`,
+  for arbitrary :math:`\delta`.
 
 Background
 ----------
 
-The algorithms implemented by this package are given in Karney (2013)
-and are based on Bessel (1825) and Helmert (1880); the algorithm for
-areas is based on Danielsen (1989).  These improve on the work of
-Vincenty (1975) in the following respects:
+The algorithms implemented by this package are given in [Karney2013]_
+and are based on [Bessel1825]_ and [Helmert1880]_; the algorithm for
+areas is based on [Danielsen1989]_.  These improve on the work of
+[Vincenty1975]_ in the following respects:
 
 * The results are accurate to round-off for terrestrial ellipsoids (the
   error in the distance is less then 15 nanometers, compared to 0.1 mm
@@ -178,40 +170,5 @@ Vincenty (1975) in the following respects:
   geodesic.  This allows, for example, the area of a geodesic polygon to
   be computed.
 
-References
-----------
-
-* F. W. Bessel,
-  `The calculation of longitude and latitude from geodesic measurements (1825)
-  <https://arxiv.org/abs/0908.1824>`_,
-  Astron. Nachr. **331**\ (8), 852–861 (2010),
-  translated by C. F. F. Karney and R. E. Deakin.
-* F. R. Helmert,
-  `Mathematical and Physical Theories of Higher Geodesy, Vol 1
-  <https://doi.org/10.5281/zenodo.32050>`_,
-  (Teubner, Leipzig, 1880), Chaps. 5–7.
-* T. Vincenty,
-  `Direct and inverse solutions of geodesics on the ellipsoid with
-  application of nested equations
-  <http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf>`_,
-  Survey Review **23**\ (176), 88–93 (1975).
-* J. Danielsen,
-  `The area under the geodesic
-  <https://doi.org/10.1179/003962689791474267>`_,
-  Survey Review **30**\ (232), 61–66 (1989).
-* C. F. F. Karney,
-  `Algorithms for geodesics
-  <https://doi.org/10.1007/s00190-012-0578-z>`_,
-  J. Geodesy **87**\ (1) 43–55 (2013);
-  `addenda <https://geographiclib.sourceforge.io/geod-addenda.html>`_.
-* C. F. F. Karney,
-  `Geodesics on an ellipsoid of revolution
-  <https://arxiv.org/abs/1102.1215v1>`_,
-  Feb. 2011;
-  `errata
-  <https://geographiclib.sourceforge.io/geod-addenda.html#geod-errata>`_.
-* `A geodesic bibliography
-  <https://geographiclib.sourceforge.io/geodesic-papers/biblio.html>`_.
-* The wikipedia page,
-  `Geodesics on an ellipsoid
-  <https://en.wikipedia.org/wiki/Geodesics_on_an_ellipsoid>`_.
+Additional background material is provided in [GeodesicBib]_,
+[GeodesicWiki]_, and [Karney2011]_.
diff --git a/docs/source/references.rst b/docs/source/references.rst
index 31100ded..e80e8caf 100644
--- a/docs/source/references.rst
+++ b/docs/source/references.rst
@@ -5,30 +5,110 @@ References
 ================================================================================
 
 
-.. [Evenden1995] Evenden, G. I., 1995, `Cartograpic Projection Procedures for the UNIX Environment - A User's Manual <https://github.com/OSGeo/proj.4/blob/master/docs/old/proj_4_3_12.pdf>`_
-
-.. [Evenden2005] Evenden, G. I., 2005, `libproj4: A Comprehensive Library of Cartographic Projection Functions (Preliminary Draft) <https://github.com/OSGeo/proj.4/blob/master/docs/old/libproj.pdf>`_
-
-.. [Steers1970] Steers, J.A., 1970, An introduction to the study of map projections (15th ed.): London, Univ. London Press, p. 229
-
-.. [Snyder1987] Snyder. John P. 1987. `Map Projections - A Working Manual <https://github.com/OSGeo/proj.4/blob/master/docs/old/USGS-Snyder-Map-Projections-A-Working-Manual-1987.pdf>`_. US. Geological Survey professional paper; 1395.
-
-.. [Snyder1993] Snyder, 1993, Flattening the Earth, Chicago and London, The university of Chicago press
-
-.. [EberHewitt1979] Eber, L.E., and R.P. Hewitt. 1979. `Conversion algorithms for the CALCOFI station grid <http://www.calcofi.org/publications/calcofireports/v20/Vol_20_Eber___Hewitt.pdf>`__. California Cooperative Oceanic Fisheries Investigations Reports 20:135-137.
-
-.. [WeberMoore2013] Weber, E.D., and T.J. Moore. 2013. `Corrected Conversion Algorithms For The Calcofi Station Grid And Their Implementation In Several Computer Languages <http://calcofi.org/publications/calcofireports/v54/Vol_54_Weber.pdf>`__. California Cooperative Oceanic Fisheries Investigations Reports 54.
-
-.. [CalabrettaGreisen2002]  M. Calabretta and E. Greisen, 2002, "Representations of celestial coordinates in FITS". Astronomy & Astrophysics 395, 3, 1077–1122.
-
-.. [ChanONeil1975]  F. Chan and E.M.O'Neill, 1975, "Feasibility Study of a Quadrilateralized Spherical Cube Earth Data Base". Tech. Rep. EPRF 2-75 (CSC), Environmental Prediction Research Facility.
-
-.. [ONeilLaubscher1976] E.M. O'Neill and R.E. Laubscher, 1976, "Extended Studies of a Quadrilateralized Spherical Cube Earth Data Base". Tech. Rep. NEPRF 3-76 (CSC), Naval Environmental Prediction Research Facility.
-
-.. [LambersKolb2012] M. Lambers and A. Kolb, 2012, "Ellipsoidal Cube Maps for Accurate Rendering of Planetary-Scale Terrain Data", Proc. Pacfic Graphics (Short Papers).
-
-.. [Zajac1978] A. Zajac, 1978, "Atlas of distribution of vascular plants in Poland (ATPOL)". Taxon 27(5/6), 481–484. 
-
-.. [Komsta2016] L. Komsta, 2016, `ATPOL geobotanical grid revisited – a proposal of coordinate conversion algorithms <http://wydawnictwo.up.lublin.pl/annales/Agricultura/2016/1/03.pdf>`__. Annales UMCS Sectio E Agricultura 71(1), 31-37.
-
-.. [Verey2017] M. Verey, 2017, `Theoretical analysis and practical consequences of adopting an ATPOL grid model as a conical projection, defining the conversion of plane coordinates to the WGS - 84 ellipsoid <http://www.botany.pl/atpol/Siatka%20ATPOL%20w%20analitycznym%20ujeciu.pdf>`__. Fragmenta Floristica et Geobotanica Polonica (preprint submitted).
+.. [Bessel1825] F. W. Bessel, 1825,
+   `The calculation of longitude and latitude from geodesic measurements
+   <https://arxiv.org/abs/0908.1824>`_,
+   Astron. Nachr. **331**\ (8), 852–861 (2010),
+   translated by C. F. F. Karney and R. E. Deakin.
+
+.. [CalabrettaGreisen2002] M. Calabretta and E. Greisen, 2002,
+   "Representations of celestial coordinates in FITS".
+   Astronomy & Astrophysics 395, 3, 1077–1122.
+
+.. [ChanONeil1975]  F. Chan and E. M. O'Neill, 1975,
+   "Feasibility Study of a Quadrilateralized Spherical Cube Earth Data Base",
+   Tech. Rep. EPRF 2-75 (CSC), Environmental Prediction Research Facility.
+
+.. [Danielsen1989] J. Danielsen, 1989,
+   `The area under the geodesic
+   <https://doi.org/10.1179/003962689791474267>`_,
+   Survey Review **30**\ (232), 61–66.
+
+.. [EberHewitt1979] L. E. Eber and R.P. Hewitt, 1979,
+   `Conversion algorithms for the CALCOFI station grid
+   <http://www.calcofi.org/publications/calcofireports/v20/Vol_20_Eber___Hewitt.pdf>`_,
+   California Cooperative Oceanic Fisheries Investigations Reports 20:135-137.
+
+.. [Evenden1995] G. I. Evenden, 1995,
+   `Cartograpic Projection Procedures for the UNIX Environment -
+   A User's Manual
+   <https://github.com/OSGeo/proj.4/blob/master/docs/old/proj_4_3_12.pdf>`_.
+
+.. [Evenden2005] G. I. Evenden, 2005,
+   `libproj4: A Comprehensive Library of Cartographic Projection Functions
+   (Preliminary Draft)
+   <https://github.com/OSGeo/proj.4/blob/master/docs/old/libproj.pdf>`_.
+
+.. [GeodesicBib] `A geodesic bibliography
+   <https://geographiclib.sourceforge.io/geodesic-papers/biblio.html>`_.
+
+.. [GeodesicWiki] The wikipedia page,
+   `Geodesics on an ellipsoid
+   <https://en.wikipedia.org/wiki/Geodesics_on_an_ellipsoid>`_.
+
+.. [Helmert1880] F. R. Helmert, 1880,
+   `Mathematical and Physical Theories of Higher Geodesy, Vol 1
+   <https://doi.org/10.5281/zenodo.32050>`_,
+   (Teubner, Leipzig), Chaps. 5–7.
+
+.. [Karney2011] C. F. F. Karney, 2011,
+   `Geodesics on an ellipsoid of revolution
+   <https://arxiv.org/abs/1102.1215v1>`_;
+   `errata
+   <https://geographiclib.sourceforge.io/geod-addenda.html#geod-errata>`_.
+
+.. [Karney2013] C. F. F. Karney, 2013,
+   `Algorithms for geodesics
+   <https://doi.org/10.1007/s00190-012-0578-z>`_,
+   J. Geodesy **87**\ (1) 43–55;
+   `addenda <https://geographiclib.sourceforge.io/geod-addenda.html>`_.
+
+.. [Komsta2016] L. Komsta, 2016,
+   `ATPOL geobotanical grid revisited - a proposal of coordinate conversion
+   algorithms
+   <http://wydawnictwo.up.lublin.pl/annales/Agricultura/2016/1/03.pdf>`_,
+   Annales UMCS Sectio E Agricultura 71(1), 31–37.
+
+.. [LambersKolb2012] M. Lambers and A. Kolb, 2012,
+   "Ellipsoidal Cube Maps for Accurate Rendering of Planetary-Scale
+   Terrain Data", Proc. Pacfic Graphics (Short Papers).
+
+.. [ONeilLaubscher1976] E. M. O'Neill and R. E. Laubscher, 1976,
+   "Extended Studies of a Quadrilateralized Spherical Cube Earth Data Base",
+   Tech. Rep. NEPRF 3-76 (CSC),
+   Naval Environmental Prediction Research Facility.
+
+.. [Snyder1987] J. P. Snyder, 1987,
+   `Map Projections - A Working Manual
+   <https://pubs.er.usgs.gov/publication/pp1395>`_.
+   U.S. Geological Survey professional paper 1395.
+
+.. [Snyder1993] J. P. Snyder, 1993,
+   Flattening the Earth, Chicago and London, The University of Chicago press.
+
+.. [Steers1970] J. A. Steers, 1970,
+   An introduction to the study of map projections (15th ed.),
+   London Univ. Press, p. 229.
+
+.. [Verey2017] M. Verey, 2017,
+   `Theoretical analysis and practical consequences of adopting an ATPOL
+   grid model as a conical projection, defining the conversion of plane
+   coordinates to the WGS-84 ellipsoid
+   <http://www.botany.pl/atpol/Siatka%20ATPOL%20w%20analitycznym%20ujeciu.pdf>`_,
+   Fragmenta Floristica et Geobotanica Polonica (preprint submitted).
+
+.. [Vincenty1975] T. Vincenty, 1975,
+   `Direct and inverse solutions of geodesics on the ellipsoid with
+   application of nested equations
+   <http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf>`_,
+   Survey Review **23**\ (176), 88–93.
+
+.. [WeberMoore2013] E. D. Weber and T.J. Moore, 2013,
+   `Corrected Conversion Algorithms For The Calcofi Station Grid And Their
+   Implementation In Several Computer Languages
+   <http://calcofi.org/publications/calcofireports/v54/Vol_54_Weber.pdf>`_,
+   California Cooperative Oceanic Fisheries Investigations Reports 54.
+
+.. [Zajac1978] A. Zajac, 1978,
+   "Atlas of distribution of vascular plants in Poland (ATPOL)",
+   Taxon 27(5/6), 481–484.