NSArray *arrayOfTitles = [[[fetchedResultsController fetchedObjects]
                                           valueForKey:@"packTitle"]
                                       valueForKeyPath:@"@distinctUnionOfObjects.self"];

- (NSArray *) cardsForPackTitle:(NSString * )selectedPackTitle {

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Card" inManagedObjectContext:managedObjectContext];

    [fetchRequest setEntity:entity];

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(packTitle like %@)", selectedPackTitle];

    [fetchRequest setPredicate:predicate];

    NSError *error;

    NSArray *fetchedCards =  [managedObjectContext executeFetchRequest:fetchRequest error:&error ];

    [fetchRequest release];

     return fetchedCards;

}