Comparing mental and physical health of U.S. veterans by VA healthcare use: implications for generalizability of research in the VA electronic health records oleh David S. Fink, Malka Stohl, Zachary L. Mannes, Dvora Shmulewitz, Melanie Wall, Sarah Gutkind, Mark Olfson, Jaimie Gradus, Salomeh Keyhani, Charles Maynard, Katherine M. Keyes, Scott Sherman, Silvia Martins, Andrew J. Saxon, Deborah S. Hasin