diff --git a/src/main/java/seedu/address/logic/commands/DeleteTagCommand.java b/src/main/java/seedu/address/logic/commands/DeleteTagCommand.java
index 50231c00699..c22db357c7d 100644
--- a/src/main/java/seedu/address/logic/commands/DeleteTagCommand.java
+++ b/src/main/java/seedu/address/logic/commands/DeleteTagCommand.java
@@ -12,8 +12,8 @@
 import seedu.address.model.tag.Tag;
 
 /**
- * Implements command to delete a tag from a person
- * format: deltag [INDEX] t/[TAG NAME]
+ * Implements command to delete a tag from a person.
+ * format: deltag [INDEX] t/[TAG NAME].
  */
 public class DeleteTagCommand extends Command {
     public static final String COMMAND_WORD = "deltag";
diff --git a/src/main/java/seedu/address/logic/parser/DeleteTagCommandParser.java b/src/main/java/seedu/address/logic/parser/DeleteTagCommandParser.java
index 8b7212c6975..07edf19b938 100644
--- a/src/main/java/seedu/address/logic/parser/DeleteTagCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/DeleteTagCommandParser.java
@@ -12,17 +12,16 @@
 import seedu.address.model.tag.Tag;
 
 /**
- * Parse the delete tag command.
+ * Parses the delete tag command.
  */
 public class DeleteTagCommandParser implements Parser<DeleteTagCommand> {
     /**
-     * Parses the given string of arguments in the context of Delete tag command.
+     * Parses the given string of arguments in the context of delete tag command.
      * and returns DeleteTagCommand object for execution.
      * @throws ParseException if user input does not conform the expected input
      */
     public DeleteTagCommand parse(String args) throws ParseException {
         requireNonNull(args);
-        // assert !args.isEmpty(); // This causes error to not be displayed properly
         ArgumentMultimap argMultiMap = ArgumentTokenizer.tokenize(args, PREFIX_TAG);
 
         Index index;
diff --git a/src/main/java/seedu/address/model/CampusConnect.java b/src/main/java/seedu/address/model/CampusConnect.java
index fc1e5019b1a..2a0ba23db24 100644
--- a/src/main/java/seedu/address/model/CampusConnect.java
+++ b/src/main/java/seedu/address/model/CampusConnect.java
@@ -4,7 +4,6 @@
 
 import java.util.List;
 import java.util.Set;
-import java.util.Stack;
 
 import javafx.collections.ObservableList;
 import seedu.address.commons.util.ToStringBuilder;
@@ -16,15 +15,12 @@
 import seedu.address.model.tag.TagCategory;
 
 /**
- * Wraps all data at the CampusConnect level
- * Duplicates are not allowed (by .isSamePerson comparison)
+ * Wraps all data at the CampusConnect level.
+ * Duplicates are not allowed.
  */
 public class CampusConnect implements ReadOnlyCampusConnect {
 
     private final UniquePersonList persons;
-    private final Stack<ReadOnlyCampusConnect> prev = new Stack<>();
-    private final Stack<ReadOnlyCampusConnect> future = new Stack<>();
-
     private final VersionedCampusConnect versionedCampusConnect = new VersionedCampusConnect();
 
     /*
@@ -60,7 +56,7 @@ public void saveCurrentState() {
     }
 
     /**
-     * Recovers from previous states
+     * Recovers from previous state.
      */
     public ReadOnlyCampusConnect recoverPreviousState() throws UndoException {
         ReadOnlyCampusConnect out = versionedCampusConnect.extractOldData();
@@ -69,7 +65,7 @@ public ReadOnlyCampusConnect recoverPreviousState() throws UndoException {
     }
 
     /**
-     * Recovers previously undone states
+     * Recovers the previously undone state.
      */
     public ReadOnlyCampusConnect recoverUndoneState() throws RedoException {
         ReadOnlyCampusConnect out = versionedCampusConnect.extractUndoneData();
@@ -151,7 +147,7 @@ public void removePersonTag(Person p, Tag t) {
     }
 
     /**
-     * Adds a new Tag to person
+     * Adds a new Tag to a person.
      */
     public void addPersonTags(Person p, Set<Tag> tagList) {
         persons.addPersonTags(p, tagList);
diff --git a/src/main/java/seedu/address/model/Model.java b/src/main/java/seedu/address/model/Model.java
index 6ae2d53299f..90546ca187f 100644
--- a/src/main/java/seedu/address/model/Model.java
+++ b/src/main/java/seedu/address/model/Model.java
@@ -74,12 +74,12 @@ public interface Model {
 
     /**
      * Deletes a tag from a person.
-     * The person must exist as well as the tag
+     * The person must exist as well as the tag.
      */
     void deletePersonTag(Person p, Tag tag);
 
     /**
-     * Adds a set of tag to person
+     * Adds a set of tag to person.
      */
     void addPersonTags(Person p, Set<Tag>t);
 
@@ -131,12 +131,12 @@ public interface Model {
     void updateFilteredPersonList(Predicate<Person> predicate);
 
     /**
-     * Undoes the previous actions of users
+     * Undoes the previous actions of users.
      */
     void undoCampusConnect() throws CommandException;
 
     /**
-     * Restores state before previous undo actions of users
+     * Restores state before previous undo actions of users.
      */
     void redoCampusConnect() throws CommandException;
 
diff --git a/src/main/java/seedu/address/model/VersionedCampusConnect.java b/src/main/java/seedu/address/model/VersionedCampusConnect.java
index ea3aeca3a4f..9758da55d46 100644
--- a/src/main/java/seedu/address/model/VersionedCampusConnect.java
+++ b/src/main/java/seedu/address/model/VersionedCampusConnect.java
@@ -59,7 +59,7 @@ public void saveCurrentData(ReadOnlyCampusConnect data) {
     }
 
     /**
-     * Clear all undone data in the future stack.
+     * Clears all undone data in the future stack.
      */
     public void clearUndoneData() {
         future.clear();