updated semantic annotations primer

Edited the semantic annotations primer.

docs/eml-semantic-annotations-primer.md

@@ -10,7 +10,7 @@ A semantic annotation follows the Resource Description Framework (RDF) data mode
 In **EML 2.2.0** there are 5 kinds of semantic annotations that can be made in an EML document: **dataset-level**, **entity-level**, **attribute-level**, **/eml/annotations** and **/eml/additionalMetadata**.
 
 ### Pattern for dataset-level, entity-level, and attribute-level annotations
-Semantic annotations made at the **dataset-level**, **entity-level**, and **attribute-level** follow the same pattern. An annotation made at any of these levels involves inserting an `annotation` element containing a `propertyURI` element and a `valueURI` element within the appropriate element. The *subject* of this annotation is the containing element. *It is recommended to give the subject element an* `id` *attribute and make the subject the value of the* `id`. The `propertyURI` is the *object property* and the `valueURI` is the *object* of the annotation. For example, an attribute-level annotation involves an `attribute` element. Within the `attribute` element are `propertyURI` and `valueURI` elements. 
+Semantic annotations made at the **dataset-level**, **entity-level**, and **attribute-level** follow the same pattern. An annotation made at any of these levels involves inserting an `annotation` element containing a `propertyURI` element and a `valueURI` element within the appropriate element. The *subject* of this annotation is the containing element. *It is recommended to give the subject element an* `id` *attribute and make the subject the value of the* `id`. The `propertyURI` is the *object property* and the `valueURI` is the *object* of the annotation. For example, an attribute-level annotation involves an `attribute` element. Within the `attribute` element are `propertyURI` and `valueURI` elements. The URIs should ideally point to terms in controlled vocabularies.
 
 Multiple `annotation` elements may be embedded in the same dataset, entity-level or attribute element to assert multiple semantic statements.
 
@@ -60,7 +60,7 @@ In the following dataset-level annotation (Example 1), the subject of the semant
 
 #### Entity-level annotations
 
-Entities are usually tables of data (EML element `dataTable`). Data tables may be ascii text files, relational database tables, spreadsheets or other type of tabular data with a fixed logical structure. Related to data tables are views (EML element `view`) and stored procedures (EML element `storedProcedure`). Views and stored procedures are produced by an RDBMS or related system. Other types of data such as: raster (EML element `spatialRaster`), vector (EML element `spatialVector`) or spatialReference image data are also data entities. An `otherEntity` element would be used to describe types of entities that are not described by any other entity type. Entity-level EML elements are nested under `dataset` elements. Further information about entities may be found at: [insert link].
+Entities are usually tables of data (EML element `dataTable`). Data tables may be ascii text files, relational database tables, spreadsheets or other type of tabular data with a fixed logical structure. Related to data tables are views (EML element `view`) and stored procedures (EML element `storedProcedure`). Views and stored procedures are produced by an RDBMS or related system. Other types of data such as raster (EML element `spatialRaster`), vector (EML element `spatialVector`) or spatialReference image data are also data entities. An `otherEntity` element should be used to describe types of entities that are not described by any other entity type. Entity-level EML elements are nested under `dataset` elements. Further information about entities may be found at: [insert link].
 
 An entity-level annotation represents a precisely-defined semantic statement that applies to an entity. This semantic statement is used to associate precise measurement semantics with the entity. An entity-level `annotation` element is embedded in a containing entity-level element. The subject of the semantic statement is the entity-level element that contains the annotation. If the entity-level element contains an `id` attribute, then the subject should be the value of the `id` attribute. Each annotation consists of a `propertyURI` element and `valueURI` element, which respectively define a property and a value (object) that apply to the entity. The associated labels can be used to display the property and value in a more readable format to users. Each URI should be resolvable to a controlled vocabulary that provides a precise definition, relationships to other terms, and multiple labels for displaying the statement.
 
@@ -109,7 +109,7 @@ In the following attribute annotation (Example 3), the subject of the semantic s
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 ### Pattern for /eml/annotations annotations
-Semantic annotations may also be inserted in the `annotations` element that is nested under the `eml` root element. This type of semantic annotation involves an `annotation` element that has a `references` attribute. What is listed in the `references` attribute is the *subject* of the semantic annotation. Within the `annotation` element are `propertyURI` and `valueURI` elements. The `propertyURI` is the *object property* and the `valueURI` is the *object* of the annotation.  
+Semantic annotations may also be inserted in the `annotations` element that is nested under the `eml` root element. This type of semantic annotation involves an `annotation` element that has a `references` attribute. What is listed in the `references` attribute is the *subject* of the semantic annotation. Within the `annotation` element are `propertyURI` and `valueURI` elements. The `propertyURI` is the *object property* and the `valueURI` is the *object* of the annotation. The URIs should ideally point to terms in controlled vocabularies. 
 
 Multiple `annotation` elements can be used to create multiple annotations about the same subject. 
 ```
@@ -163,7 +163,7 @@ The third semantic statement also has the subject "adam.shepherd". The object pr
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 ### Pattern for /eml/additionalMetadata annotations
-Semantic annotations may also be inserted in the `additionalMetadata` element that is nested under the `eml` root element. This type of semantic annotation has a `describes` element and a `metadata` element containing the annotation. The `metadata` element has an `annotation` element. The content of the `describes` element is the *subject* of the semantic annotation. Within the `annotation` element are `propertyURI` and `valueURI` elements. The `propertyURI` is the *object property* and the `valueURI` is the *object* of the annotation.  
+Semantic annotations may also be inserted in the `additionalMetadata` element that is nested under the `eml` root element. This type of semantic annotation has a `describes` element and a `metadata` element containing the annotation. The `metadata` element has an `annotation` element. The content of the `describes` element is the *subject* of the semantic annotation. Within the `annotation` element are `propertyURI` and `valueURI` elements. The `propertyURI` is the *object property* and the `valueURI` is the *object* of the annotation. The URIs should ideally point to terms in controlled vocabularies.
 
 Multiple `annotation` elements may be embedded in the same `metadata` element to assert multiple semantic statements about the same subject.
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