Erro após adicionar loaders

ERROR in ./node_modules/css-loader!./node_modules/style-loader!./node_modules/css-loader!./node_modules/bootstrap/dist/css/bootstrap.css
Module build failed: Unknown word (5:1)

  3 | // load the styles
  4 | var content = require("!!../../../css-loader/index.js!./bootstrap.css");
> 5 | if(typeof content === 'string') content = [[module.id, content, '']];
    | ^
  6 | // Prepare cssTransformation
  7 | var transform;
  8 |

 @ ./node_modules/bootstrap/dist/css/bootstrap.css 4:14-131
 @ ./app-src/app.js
 @ multi (webpack)-dev-server/client?http://localhost:8080 ./app-src/app.js

ERROR in ./node_modules/css-loader!./node_modules/style-loader!./node_modules/css-loader!./node_modules/bootstrap/dist/css/bootstrap-theme.css
Module build failed: Unknown word (5:1)

  3 | // load the styles
  4 | var content = require("!!../../../css-loader/index.js!./bootstrap-theme.css");
> 5 | if(typeof content === 'string') content = [[module.id, content, '']];
    | ^
  6 | // Prepare cssTransformation
  7 | var transform;
  8 |

 @ ./node_modules/bootstrap/dist/css/bootstrap-theme.css 4:14-137
 @ ./app-src/app.js
 @ multi (webpack)-dev-server/client?http://localhost:8080 ./app-src/app.js
webpack: Failed to compile.