diff -ur a/include/gemmi/json.hpp b/include/gemmi/json.hpp
--- a/include/gemmi/json.hpp
+++ b/include/gemmi/json.hpp
@@ -38,6 +38,7 @@
 
 inline std::string as_cif_value(const sajson::value& val) {
   switch (val.get_type()) {
+    case sajson::TYPE_INTEGER:
     case sajson::TYPE_DOUBLE:
       return val.as_string();
     case sajson::TYPE_NULL:
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<tr><td><span title='2019-06-15 18:24:52 +0200'>2019-06-15</span></td><td><a href='/guix/commit/gnu/packages/dico.scm?id=d2de780272a000d72c0a2d3898f968c57fd2cf2e'>gnu: dico: Update to 2.9.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dico.scm (dico): Update to 2.9.
</span></span></td><td>Ludovic Courtès</td></tr>