add system for encyclopedia article sources

css/gui/encyclopedia.css

@@ -12,3 +12,11 @@
 	white-space: nowrap;
 	font-size: smaller;
 }
+
+.encyclopedia-source::before {
+	content: "— ";
+}
+
+.encyclopedia-source .article {
+	font-style: italic;
+}

src/004-base/encyclopediaMap.js

@@ -91,3 +91,20 @@ App.Encyclopedia.renderCategory = function(article) {
 App.Encyclopedia.topic = function(topic) {
 	return App.UI.DOM.makeElement("span", topic, ["encyclopedia", "topic"]);
 };
+
+/**
+ * @param {Node} parent
+ * @param {string} source
+ * @param {string} [author]
+ */
+App.Encyclopedia.addArticleSource = function(parent, source, author) {
+	const r = [];
+
+	if (author) {
+		r.push(`<span class='author'>${author},</span>`);
+	}
+
+	r.push(`<span class='article'>${source}</span>`);
+
+	App.Events.addNode(parent, r, "p", "encyclopedia-source");
+};