diff --git a/src/main/java/org/wikitolearn/midtier/course/web/rest/ChapterController.java b/src/main/java/org/wikitolearn/midtier/course/web/rest/ChapterController.java
index 3db550a..92c0287 100644
--- a/src/main/java/org/wikitolearn/midtier/course/web/rest/ChapterController.java
+++ b/src/main/java/org/wikitolearn/midtier/course/web/rest/ChapterController.java
@@ -1,152 +1,152 @@
 package org.wikitolearn.midtier.course.web.rest;
 
 import java.util.Collections;
 import java.util.Optional;
 import java.util.stream.Collectors;
 
 import javax.validation.Valid;
 
 import org.modelmapper.ModelMapper;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PatchMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestHeader;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 import org.wikitolearn.midtier.course.entity.Chapter;
 import org.wikitolearn.midtier.course.entity.ErrorJson;
 import org.wikitolearn.midtier.course.entity.dto.in.AddChapterPagesDto;
 import org.wikitolearn.midtier.course.entity.dto.in.UpdateChapterDto;
 import org.wikitolearn.midtier.course.entity.dto.in.UpdateChapterPagesDto;
 import org.wikitolearn.midtier.course.entity.dto.out.AddedChapterPagesDto;
 import org.wikitolearn.midtier.course.entity.dto.out.GetChapterDto;
 import org.wikitolearn.midtier.course.entity.dto.out.UpdatedChapterDto;
 import org.wikitolearn.midtier.course.exception.InvalidResourceCreateException;
 import org.wikitolearn.midtier.course.service.ChapterService;
 import org.wikitolearn.midtier.course.service.PageService;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 
 import io.swagger.annotations.ApiResponse;
 import io.swagger.annotations.ApiResponses;
 import lombok.extern.slf4j.Slf4j;
 
 @RestController
 @Slf4j
 @RequestMapping(value =  "/chapters")
 public class ChapterController {
 
   @Autowired
   private ChapterService chapterService;
 
   @Autowired
   private PageService pageService;
 
   @Autowired
   private ModelMapper modelMapper;
 
   @Autowired
   private ObjectMapper objectMapper;
 
   @ApiResponses({
     @ApiResponse(code = 200, message = "Success", response = GetChapterDto.class),
     @ApiResponse(code = 404, message = "Not Found", response = ErrorJson.class)
   })
   @GetMapping(value = "/{chapterId}", produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
   public GetChapterDto getChapter(@PathVariable String chapterId) throws JsonProcessingException {
 
     MultiValueMap<String, String> pagesParams = new LinkedMultiValueMap<>();
     ObjectNode projectionJsonObject = objectMapper.getNodeFactory().objectNode().put("title", 1);
     pagesParams.add("projection", objectMapper.writeValueAsString(projectionJsonObject));
 
     Chapter chapter = chapterService.find(chapterId, null);
     chapter.setPages(
         Optional
         .ofNullable(chapter.getPages())
         .orElseGet(Collections::emptyList)
         .parallelStream()
         .map(page -> pageService.find(page.getId(), pagesParams))
         .collect(Collectors.toList())
     );
     return modelMapper.map(chapter, GetChapterDto.class);
   }
 
   @ApiResponses({
     @ApiResponse(code = 200, message = "Success", response = UpdatedChapterDto.class),
     @ApiResponse(code = 401, message = "Unauthorized"),
     @ApiResponse(code = 403, message = "Forbidden"),
     @ApiResponse(code = 404, message = "Not Found", response = ErrorJson.class),
     @ApiResponse(code = 422, message = "Uprocessable Entity"),
     @ApiResponse(code = 500, message = "Internal Server Error", response = ErrorJson.class)
   })
   @PatchMapping(value = "/{chapterId}", consumes = MediaType.APPLICATION_JSON_UTF8_VALUE, produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
-  public UpdatedChapter update(@PathVariable("chapterId") String chapterId, @Valid @RequestBody UpdateChapterDto chapter, @RequestHeader("If-Match") String etag) throws JsonProcessingException {
+  public UpdatedChapterDto update(@PathVariable("chapterId") String chapterId, @Valid @RequestBody UpdateChapterDto chapter, @RequestHeader("If-Match") String etag) throws JsonProcessingException {
     Chapter chapterToUpdate = modelMapper.map(chapter, Chapter.class);
     chapterToUpdate.setId(chapterId);
     chapterToUpdate.setEtag(etag);
 
     Chapter updatedChapter = chapterService.update(chapterToUpdate);
 
     return modelMapper.map(updatedChapter, UpdatedChapterDto.class);
   }
 
   @ApiResponses({
     @ApiResponse(code = 200, message = "Success", response = UpdatedChapterDto.class),
     @ApiResponse(code = 401, message = "Unauthorized"),
     @ApiResponse(code = 403, message = "Forbidden"),
     @ApiResponse(code = 422, message = "Uprocessable Entity"),
     @ApiResponse(code = 500, message = "Internal Server Error", response = ErrorJson.class)
   })
   @PatchMapping(value = "/{chapterId}/pages", produces = MediaType.APPLICATION_JSON_UTF8_VALUE, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
-  public UpdatedChapter updatePages(@PathVariable("chapterId") String chapterId, @Valid @RequestBody UpdateChapterPagesDto chapter, @RequestHeader("If-Match") String etag) throws JsonProcessingException, InvalidResourceCreateException {
+  public UpdatedChapterDto updatePages(@PathVariable("chapterId") String chapterId, @Valid @RequestBody UpdateChapterPagesDto chapter, @RequestHeader("If-Match") String etag) throws JsonProcessingException, InvalidResourceCreateException {
     Chapter chapterToUpdate = modelMapper.map(chapter, Chapter.class);
     chapterToUpdate.setId(chapterId);
     chapterToUpdate.setEtag(etag);
 
     Chapter updatedChapter = chapterService.updatePages(chapterToUpdate);
     return modelMapper.map(updatedChapter, UpdatedChapterDto.class);
   }
 
   @ApiResponses({
     @ApiResponse(code = 200, message = "Success", response = AddedChapterPagesDto.class),
     @ApiResponse(code = 401, message = "Unauthorized"),
     @ApiResponse(code = 403, message = "Forbidden"),
     @ApiResponse(code = 422, message = "Uprocessable Entity"),
     @ApiResponse(code = 500, message = "Internal Server Error", response = ErrorJson.class)
   })
   @PostMapping(value = "/{chapterId}/pages", produces = MediaType.APPLICATION_JSON_UTF8_VALUE, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
   public AddedChapterPagesDto addPages(@PathVariable("chapterId") String chapterId, @Valid @RequestBody AddChapterPagesDto chapter, @RequestHeader("If-Match") String etag) throws JsonProcessingException, InvalidResourceCreateException {
     Chapter chapterToUpdate = modelMapper.map(chapter, Chapter.class);
     chapterToUpdate.setId(chapterId);
     chapterToUpdate.setEtag(etag);
 
     Chapter updatedChapter = chapterService.addPages(chapterToUpdate);
     return modelMapper.map(updatedChapter, AddedChapterPagesDto.class);
   }
 
   @ApiResponses({
     @ApiResponse(code = 204, message = "No Content"),
     @ApiResponse(code = 401, message = "Unauthorized"),
     @ApiResponse(code = 403, message = "Forbidden"),
     @ApiResponse(code = 500, message = "Internal Server Error", response = ErrorJson.class)
   })
   @DeleteMapping(value = "/{chapterId}")
   @ResponseStatus(HttpStatus.NO_CONTENT)
   public void delete(@PathVariable("chapterId") String chapterId, @RequestHeader("If-Match") String etag) throws JsonProcessingException {
     Chapter chapter = new Chapter();
     chapter.setId(chapterId);
     chapter.setEtag(etag);
     chapterService.delete(chapter, false);
   }
 }