Includes reference to the definition

Author: GeoffreySangston

spaces/S000106/README.md

@@ -8,6 +8,14 @@ refs:
     name: Answer to "Is the weak topology on $\mathbb{R}^{\infty}$ the same as the box topology?"
   - mathse: 5012784
     name: Answer to "Is $\ell^\infty$ with box topology connected?"
+  - zb: "0298.57008"
+    name: Characteristic classes (Milnor-Stasheff)
+  - zb: "0307.55015"
+    name: Fibre bundles. 2nd ed. (Husemoller)
+  - zb: "1280.54001"
+    name: Geometric aspects of general topology. (Sakai)
+  - wikipedia: Fréchet–Urysohn_space
+    name: Fréchet–Urysohn space on Wikipedia
 ---
 The subset $\mathbb{R}^\infty$ of eventually $0$ sequences in $\mathbb{R}^\omega$, with the finest 
 topology such that the standard inclusion maps $\mathbb{R}^n \hookrightarrow \mathbb{R}^\infty$, 
@@ -30,3 +38,7 @@ $\mathbb{R}^\omega$. Hence $\mathbb{R}^\infty$ embeds into {{S107}}
 as a path component.
 
 For general discussion on direct limits, see {{wikipedia:Direct_limit}}.
+
+Defined on page 62 of {{zb:"0298.57008"}}, on page 2 of {{zb:"0307.55015"}}, 
+on page 56 of {{zb:"1280.54001}}, and on {{wikipedia:Fréchet–Urysohn_space}} 
+under Direct limit of finite-dimensional Euclidean spaces.