diff --git a/README.md b/README.md
index b92ce9b..d3b77d4 100644
--- a/README.md
+++ b/README.md
@@ -98,6 +98,20 @@ Just use the liquid tags `{% highlight python %}` and `{% endhighlight %}` to de
   </a>
 </p>
 
+#### Social media previews
+The al-folio theme optionally supports preview images on social media.
+To enable this functionality you will need to set `serve_og_meta` to `true` in
+your `_config.yml`. Once you have done so, all your site's pages will include
+Open Graph data in the HTML head element.
+
+You will then need to configure what image to display in your site's social
+media previews. This can be configured on a per-page basis, by setting the
+`og_image` page variable. If for an individual page this variable is not set,
+then the theme will fall back to a site-wide `og_image` variable, configurable
+in your `_config.yml`. In both the page-specific and site-wide cases, the
+`og_image` variable needs to hold the URL for the image you wish to display in
+social media previews.
+
 ## Contributing
 
 Feel free to contribute new features and theme improvements by sending a pull request.
diff --git a/_bibliography/papers.bib b/_bibliography/papers.bib
index eb9851e..a31c66d 100644
--- a/_bibliography/papers.bib
+++ b/_bibliography/papers.bib
@@ -34,7 +34,9 @@
   month={May},
   publisher=aps,
   doi={10.1103/PhysRev.47.777},
-  url={http://link.aps.org/doi/10.1103/PhysRev.47.777}
+  url={http://link.aps.org/doi/10.1103/PhysRev.47.777},
+  html={https://journals.aps.org/pr/abstract/10.1103/PhysRev.47.777},
+  pdf={example_pdf.pdf}
 }
 
 @article{einstein1905molekularkinetischen,
diff --git a/_config.yml b/_config.yml
index f78604e..972b596 100644
--- a/_config.yml
+++ b/_config.yml
@@ -23,6 +23,14 @@ navbar_fixed: true
 footer_fixed: true
 # TODO: add layout settings (single page vs. multi-page)
 
+# -----------------------------------------------------------------------------
+# Open Graph
+# -----------------------------------------------------------------------------
+# Display links to the page with a preview object on social media.
+# To achieve this, change serve_og_meta to true and then provide the URL of the
+# preview image as the value of og_image.
+serve_og_meta: false # Include Open Graph meta tags in the HTML head
+og_image: # The site-wide (default for all links) Open Graph preview image
 # -----------------------------------------------------------------------------
 # Social integration
 # -----------------------------------------------------------------------------
@@ -32,6 +40,12 @@ twitter_username: # your Twitter handle
 linkedin_username: # your LinkedIn user name
 scholar_userid: # your Google Scholar ID
 orcid_id: # your ORCID ID
+medium_username: # your Medium username
+quora_username: # your Quora username
+publons_id: # your ID on Publons
+research_gate_profile: # your profile on ResearchGate
+blogger_url: # your blogger URL
+
 contact_note: >
   You can even add a little note about which of these is the best way to reach you.
 
diff --git a/_includes/head.html b/_includes/head.html
index 32717d0..d2cc3bb 100644
--- a/_includes/head.html
+++ b/_includes/head.html
@@ -19,3 +19,13 @@
 <link rel="stylesheet" href="{{ '/assets/css/main.css' | relative_url }}">
 
 <link rel="canonical" href="{{ page.url | replace:'index.html','' | relative_url }}">
+
+<!-- Open Graph -->
+{% if site.serve_og_meta %}
+<meta property="og:site_name" content="{{ site.description }}" />
+<meta property="og:type" content="object" />
+<meta property="og:title" content="{{ site.name }}" />
+<meta property="og:url" content="{{ page.url | prepend: site.baseurl | prepend: site.url }}" />
+<meta property="og:description" content="{{ page.title }}" />
+<meta property="og:image" content="{%- if page.og_image -%}{{ page.og_image }}{%- else -%}{{ site.og_image }}{%- endif -%}" />
+{% endif %}
diff --git a/_includes/social.html b/_includes/social.html
index 28133ab..c706aff 100644
--- a/_includes/social.html
+++ b/_includes/social.html
@@ -2,8 +2,13 @@
   <a href="mailto:{{ site.email | encode_email }}"><i class="fas fa-envelope"></i></a>
   {% if site.orcid_id %}<a href="https://orcid.org/{{ site.orcid_id }}" target="_blank" title="ORCID"><i class="ai ai-orcid"></i></a>{% endif %}
   {% if site.scholar_userid %}<a href="https://scholar.google.com/citations?user={{ site.scholar_userid }}" target="_blank" title="Google Scholar"><i class="ai ai-google-scholar"></i></a>{% endif %}
+  {% if site.publons_id %}<a href="https://publons.com/a/{{ site.publons_id }}/" target="_blank" title="Publons"><i class="ai ai-publons"></i></a>{% endif %}
+  {% if site.research_gate_profile %}<a href="https://www.researchgate.net/profile/{{site.research_gate_profile}}/" target="_blank" title="ResearchGate"><i class="ai ai-researchgate"></i></a>{% endif %}
   {% if site.github_username %}<a href="https://github.com/{{ site.github_username }}" target="_blank" title="GitHub"><i class="fab fa-github"></i></a>{% endif %}
   {% if site.linkedin_username %}<a href="https://www.linkedin.com/in/{{ site.linkedin_username }}" target="_blank" title="LinkedIn"><i class="fab fa-linkedin"></i></a>{% endif %}
   {% if site.twitter_username %}<a href="https://twitter.com/{{ site.twitter_username }}" target="_blank" title="Twitter"><i class="fab fa-twitter"></i></a>{% endif %}
+  {% if site.medium_username %}<a href="https://medium.com/@{{ site.medium_username }}" target="_blank" title="Medium"><i class="fab fa-medium"></i></a>{% endif %}
+  {% if site.quora_username %}<a href="https://www.quora.com/profile/{{ site.quora_username }}" target="_blank" title="Quora"><i class="fab fa-quora"></i></a>{% endif %}
+  {% if site.blogger_url %}<a href="{{ site.blogger_url }}" target="_blank" title="Blogger"><i class="fab fa-blogger-b"></i></a>{% endif %}
   {% if site.strava_userid %}<a href="https://www.strava.com/athletes/{{ site.strava_userid }}" target="_blank" title="Strava"><i class="fab fa-strava"></i></a>{% endif %}
 </span>
diff --git a/_sass/_base.scss b/_sass/_base.scss
index 646d308..82f6667 100644
--- a/_sass/_base.scss
+++ b/_sass/_base.scss
@@ -2,7 +2,7 @@
  * Styles for the base elements of the theme.
  ******************************************************************************/
 
- // Typography
+// Typography
 
 a, table.table a {
   color: $theme-color;
diff --git a/assets/pdf/example_pdf.pdf b/assets/pdf/example_pdf.pdf
new file mode 100644
index 0000000..b1f80db
Binary files /dev/null and b/assets/pdf/example_pdf.pdf differ