Add DOIs to doc/usage, doc/index, and README

README.md

@@ -4,6 +4,8 @@ Tools for the iTEM databases
 [![Build Status](https://travis-ci.org/transportenergy/database.svg?branch=master)](https://travis-ci.org/transportenergy/database)
 ![Codecov](https://img.shields.io/codecov/c/gh/transportenergy/database.svg)
 [![Documentation Status](https://readthedocs.org/projects/transportenergy/badge/?version=latest)](https://transportenergy.readthedocs.io/en/latest/?badge=latest)
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.4271789.svg)](https://doi.org/10.5281/zenodo.4271789)
+
 
 This repository contains tools for two databases maintained by [iTEM](https://transportenergy.org), the **International Transport Energy Modeling** consortium:
 
@@ -24,7 +26,7 @@ Copyright © 2017–2020, [iTEM contributors](https://github.com/transportenergy
 Licensed under the GNU General Public License, version 3.
 The full text of the license is available in the file `LICENSE`.
 
-See the online documentation for [citation of this software](https://transportenergy.readthedocs.io) in scientific publications that use the software *or* the resulting database.
+See the online documentation for [citation of this software](https://transportenergy.readthedocs.io/#citation) in scientific publications that use the software *or* the resulting database.
 
 Related repositories
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doc/index.rst

@@ -58,3 +58,7 @@ License
 Copyright © 2017–2020 iTEM contributors
 
 The software is licensed under the `GNU General Public License, version 3 <http://www.gnu.org/licenses/gpl-3.0.en.html>`_.
+
+.. _citation:
+
+If you use or reference data from either iTEM database, or use the code, in preparation of any scientific publication, please :ref:`cite the appropriate reference <usage-cite>`.

doc/usage.rst

@@ -18,6 +18,7 @@ Both the Python and R tools will operate on data stored in the following way; se
 
 Installation
 ============
+
 Use `pip <https://pip.pypa.io/en/stable/>`_.
 From source (for instance, to develop the code locally)::
 
@@ -49,3 +50,20 @@ The command-line option ``--local-data`` must be defined in order for these test
     $ py.test --local-data=../../data/model/database item
     ================ test session starts ================
     …
+
+
+.. _usage-cite:
+
+Cite the data or code
+=====================
+
+If you use or reference data from either iTEM database, or use the code, in preparation of any scientific publication, please cite the appropriate reference.
+
+- Automatically-generated DOIs via Zenodo, either:
+
+  - `10.5281/zenodo.4271788 <https://doi.org/10.5281/zenodo.4271788>`_, which represents *all versions* of the software, and always resolves to the latest version, or
+  - the DOI for a *specific version*. For instance, `10.5281/zenodo.4271789 <https://doi.org/10.5281/zenodo.4271789>`_ is the DOI for :mod:`item` version 2020.11.13.
+
+- DOI `10.5281/zenodo.4121180 <https://doi.org/10.5281/zenodo.4121180>`_ for the 2020-04-15 version of the historical database, which includes a snapshot of the data and a PDF document describing some of the data cleaning steps.
+
+The Zenodo pages provide downloadable citations in BibTeX and many other formats, for use in the reference management software of your choice.