There are other things worth reading, although some of them are only tangentially related to Dzogchen. In no particular order:
Germano, David Francis (1992). "Poetic thought, the intelligent Universe, and the mystery of self: The Tantric synthesis of rDzogs Chen in fourteenth century Tibet." The University of Wisconsin, Madison. Doctoral thesis. Source:
Dalton, Jacob (2005). "A Crisis of Doxography: How Tibetans Organized Tantra during the 8th-12th Centuries". Journal of the International Association of Buddhist Studies 28:1: 115–181. http://www.scribd.com/doc/49504020/A-Crisis-of-Doxography-How-Tibetans-Organized-Tantra-during-the-8th-12th-Centuries
Dalton, Jacob "The Development of Perfection: The Interiorization of Buddhist Ritual in the Eight and Ninth Centuries." Journal of Indian Philosophy 32: 1–30, 2004.
Dalton, Jacob. 2004. “The Early Development of the Padmasambhava Legend in Tibet: A Study of IOL Tib J 644 and Pelliot tibétain 307 Journal of the American Oriental Society 124.4 (2004)
Mayer, Robert. "Caskets of Treasures and Visions of Buddhas: Indic antecedents qf the Tibetan gTer-rna Tradition" in Indian Insights: Buddhism, Brahmanism and Bhaktihttp://www.scribd.com/doc/50876375/Indian-Insights-Buddhism-Brahmanism-and-Bhakti
Germano, David. "Dzogchen" by ENCYCLOPEDIA OF RELIGION, 2nd ed.
Martin, Dan (1987). "Illusion Web: Locating the Guhyagarbha Tantra in Buddhist Intellectual History". In Beckwith, Christopher I. Silver on Lapis: Tibetan Literary Culture and History. Bloomington: The Tibet Society. pp. 175–220
Meinert, Carmen. 2007. “The Conjunction of Chinese Chan and Tibetan rDzogs chen Thought: Reflections on the Tibetan Dunhuang Manuscripts IOL Tib J 689-1 and PT 699″, in: Contributions to the Cultural History of Early Tibet Matthew T. Kapstein/Brandon Dotson (eds.), Leiden/Boston: Brill, 239-301.
Butters, Albion Moonlight, "The doxographical genius of Kun mkhyen kLong chen rab 'byams pa." by Ph.D. dissertation, COLUMBIA UNIVERSITY, 2006
Garson, Nathaniel DeWitt (2004) Penetrating the Secret Essence Tantra: Context and Philosophy in the Mahāyoga System of rNying-ma Tantra. PhD Thesis. Department of Religious Studies, University of Virginia
Dorji, Wangchuk (2002). "An Eleventh-Century Defence of the Authenticity of the Guhyagarbha Tantra". In Eimer; Germano, David. The Many Canons of Tibetan Buddhism. Leiden: Brill
Van Schaik, Sam (2007). "In search of the Guhyagarbha tantra". EarlyTibet.com.
A. W. Hanson-Barber, The Life and Teachings of Vairocana, Phd disseration, University of Wisconsin, Madison, 1984;
Janet Gyatso "The Logic of Legitimation in the Tibetan Treasure Tradition" History of Religions, Vol. 33, No. 2 (Nov., 1993), pp. 97-
Anspal, Sten (2005). The Space Section of the Great Perfection (rDzogs-chen klong-sde): a category of philosophical and meditative teachings in Tibetan Buddhism. MA Thesis. The University of Oslo.
Van Schaik, Sam “Where Chan and Tantra Meet: Buddhist Syncretism in Dunhuang” (with Jacob Dalton) in Susan Whitfield (ed), The Silk Road: Trade, Travel, War and Faith. London: British Library Press, 2004. 61–71.
Van Schaik, Sam “The Great Perfection and the Chinese Monk: rNying-ma-pa defences of Hwa-shang Mahāyāna in the Eighteenth Century” in Buddhist Studies Review 20.2 (2003): 189–204.
Van Schaik, Sam “The Resolution of the Simultaneous and Gradual Approaches to the Great Perfection in the Klong chen snying thig” in Religion and Secular Culture in Tibet (Proceedings of the Ninth Seminar of the International Association for Tibetan Studies, Leiden 2000), ed. Henk Blezer. Leiden: EJ Brill, 2002: 309–320.
Jann M. Ronis, “Celibacy, Revelations, and Reincarnated Lamas: Contestation and Synthesis in the Growth of Monasticism at Katok Monastery from the 17th through 19th Centuries”