fix internal link issues index.md

source/presentation/4.0/index.md

@@ -229,14 +229,14 @@ A Container that represents a boundless three-dimensional space and has content
 * has optional continuous duration in seconds
 
 A Scene in IIIF is a virtual container that represents a boundless three-dimensional space and has content resources, lights and cameras positioned at locations within it. It may also have a duration to allow the sequencing of events and timed media. Scenes have infinite height (y axis), width (x axis) and depth (z axis), where 0 on each axis (the origin of the coordinate system) is treated as the center of the scene's space. 
-The positive y axis points upwards, the positive x axis points to the right, and the positive z axis points forwards (a [right-handed cartesian coordinate system](link to wikipedia)).
+The positive y axis points upwards, the positive x axis points to the right, and the positive z axis points forwards (a [right-handed cartesian coordinate system](https://en.wikipedia.org/wiki/Right-hand_rule)).
 
-The axes of the coordinate system are measured in arbitrary units and these units do not necessarily correspond to any physical unit of measurement. This allows arbitrarily scaled models to be used, including very small or very large, without needing to deal with very small or very large values. If there is a correspondence to a physical scale, then this can be asserted using the [physical dimensions pattern](fwd-ref-to-phys-dims).
+The axes of the coordinate system are measured in arbitrary units and these units do not necessarily correspond to any physical unit of measurement. This allows arbitrarily scaled models to be used, including very small or very large, without needing to deal with very small or very large values. If there is a correspondence to a physical scale, then this can be asserted using the physical dimensions pattern(fwd-ref-to-phys-dims).
 
 <img src="https://raw.githubusercontent.com/IIIF/3d/eds/assets/images/right-handed-cartesian.png" title="Right handed cartesian coordinate system" alt="diagram of Right handed cartesian coordinate system" width=200 />
 
 
-As with other containers in IIIF, Annotations are used to target the Scene to place content such as 3d models into the scene. Annotations are also used to add lights and cameras. A Scene can have multiple models, lights, cameras and other resources, allowing them to be grouped together. Scenes and other IIIF containers, such as Canvases, may also be embedded within Scenes, as described below in the [nesting section][fwd-ref-to-nesting]. 
+As with other containers in IIIF, Annotations are used to target the Scene to place content such as 3d models into the scene. Annotations are also used to add lights and cameras. A Scene can have multiple models, lights, cameras and other resources, allowing them to be grouped together. Scenes and other IIIF containers, such as Canvases, may also be embedded within Scenes, as described below in the nesting section [fwd-ref-to-nesting]. 
 
 ```json
 {