Releasing Objects when using a UINavigationController

OpenPageViewController *varOpenPageController = [[OpenPageViewController alloc] initWithNibName:@"OpenPageViewController" bundle:nil];
varOpenPageController.bookObj = bookObj;
[[self navigationController] pushViewController:varOpenPageController animated:YES];
//[varOpenPageController release];

Page *pageObj = [[bookObj pagesArray] objectAtIndex:currentPage];
pageObj.page_Text = textView.text;
[[bookObj pagesArray] replaceObjectAtIndex:currentPage withObject:pageObj];
//[pageObj release];