Add the citation information of the PyGMT paper to CITATION.cff and README.md (#4713)

Co-authored-by: Yvonne Fröhlich <94163266+yvonnefroehlich@users.noreply.github.com>

Author: seisman

CITATION.cff

@@ -88,3 +88,44 @@ repository-code: 'https://github.com/GenericMappingTools/pygmt'
 license: BSD-3-Clause
 version: 0.18.0
 date-released: '2026-01-12'
+preferred-citation:
+  type: article
+  authors:
+    - given-names: Dongdong
+      family-names: Tian
+      affiliation: 'China University of Geosciences, China'
+      orcid: 'https://orcid.org/0000-0001-7967-1197'
+    - given-names: Yvonne
+      family-names: Fröhlich
+      affiliation: 'Karlsruhe Institute of Technology, Germany'
+      orcid: 'https://orcid.org/0000-0002-8566-0619'
+    - given-names: Wei Ji
+      family-names: Leong
+      affiliation: 'Development Seed, USA'
+      orcid: 'https://orcid.org/0000-0003-2354-1988'
+    - given-names: Michael
+      family-names: Grund
+      affiliation: 'SNP Innovation Lab GmbH, Germany'
+      orcid: 'https://orcid.org/0000-0001-8759-2018'
+    - given-names: William
+      family-names: Schlitzer
+      affiliation: Unaffiliated
+      orcid: 'https://orcid.org/0000-0002-5843-2282'
+    - given-names: Max
+      family-names: Jones
+      affiliation: 'Development Seed, USA'
+      orcid: 'https://orcid.org/0000-0003-0180-8928'
+    - given-names: Leonardo
+      family-names: Uieda
+      affiliation: 'Universidade de São Paulo, Brazil'
+      orcid: 'https://orcid.org/0000-0001-6123-9515'
+    - given-names: Joaquim Manuel Freire
+      family-names: Luis
+      affiliation: 'University of Algarve, Portugal'
+      orcid: 'https://orcid.org/0000-0002-9035-4069'
+  title: 'PyGMT: Bridging Python and the Generic Mapping Tools for Geospatial Visualization and Analysis'
+  journal: 'Geochemistry, Geophysics, Geosystems'
+  volume: 27
+  article-number: e2026GC013105
+  year: 2026
+  doi: 10.1029/2026GC013105

README.md

@@ -135,8 +135,30 @@ happy to help others learn.
 PyGMT is a community developed project. See the
 [AUTHORS.md](https://github.com/GenericMappingTools/pygmt/blob/main/AUTHORS.md) file
 on GitHub for a list of the people involved and a definition of the term "PyGMT Developers".
-Feel free to cite our work in your research using the following BibTeX:
 
+Feel free to cite our work in your research. You can either cite the PyGMT paper published
+in *Geochemistry, Geophysics, Geosystems* or the Zenodo archive of the PyGMT software.
+
+The BibTeX entry for the PyGMT paper is:
+```
+@article{pygmt_2026_2026GC013105,
+  author       = {Tian, Dongdong and
+                  Fröhlich, Yvonne and
+                  Leong, Wei Ji and
+                  Grund, Michael and
+                  Schlitzer, William and
+                  Jones, Max and
+                  Uieda, Leonardo and
+                  Luis, Joaquim M. F.},
+  title        = {{PyGMT: Bridging Python and the Generic Mapping Tools for Geospatial Visualization and Analysis}},
+  journal      = {Geochemistry, Geophysics, Geosystems},
+  year         = 2026,
+  volume       = {27},
+  pages        = {e2019GC008515},
+  doi          = {10.1029/2019GC008515},
+}
+```
+The BibTeX entry for the latest Zenodo archive of the PyGMT software is:
 ```
 @software{
   pygmt_2026_18080259,