Access Firebase SDK from instance created by AngularFire2

firebase.service.ts

import { FirebaseApp } from 'angularfire2';
import { Injectable, Inject } from '@angular/core';

/**
 * After importing AngularFire2 with AngularFireModule.initializeApp(firebaseConfig),
 * you can use this to access that instance that was created with your configuration
 */

@Injectable()
export class FirebaseService {
  public authRef: any;
  public storageRef: any;
  public databaseRef: any;

  constructor(@Inject(FirebaseApp) firebase: any) {
    this.authRef = firebase.auth();
    this.storageRef = firebase.storage();
    this.databaseRef = firebase.database();
  }

  fetchProvidersForEmail(email: string) {
    return this.authRef.fetchProvidersForEmail(email);
  }

}