diff --git a/docsrc/source/usage.md b/docsrc/source/usage.md
index e5ba0706..14adced1 100644
--- a/docsrc/source/usage.md
+++ b/docsrc/source/usage.md
@@ -93,7 +93,7 @@ The API follows a hierarchy of interacting components, allowing designers to con
             from lnn import World
 
             formulae = [
-                Smoking_causes_Cancer
+                Smoking_causes_Cancer,
                 Smokers_befriend_Smokers
             ]
             model.add_knowledge(*formulae, world=World.AXIOM)
@@ -132,7 +132,8 @@ The API follows a hierarchy of interacting components, allowing designers to con
 3. Tables of Data <a name="data"></a>
    ```python
    from lnn import Fact
-   
+   # NOTE: Using .name returns a string, but add_data() expects a Formula object.
+   # This causes: TypeError: formula expected of type Formula, received str
    # add data to the model
    model.add_data({
        Friends: {
@@ -143,12 +144,12 @@ The API follows a hierarchy of interacting components, allowing designers to con
            ('Anna', 'Frank'): Fact.TRUE,
            ('Frank', 'Anna'): Fact.TRUE,
            ('Bob', 'Chris'): Fact.TRUE},
-       Smokes.name: {
+       Smokes: {
            'Anna': Fact.TRUE,
            'Edward': Fact.TRUE,
            'Frank': Fact.TRUE,
            'Gary': Fact.TRUE},
-       Cancer.name: {
+       Cancer: {
            'Anna': Fact.TRUE,
            'Edward': Fact.TRUE}
        })