found: Francke, A.H. First collection of Tibetan historical inscriptions on rock and stone from Ladakh Himalaya, 2003.
found: Zába, Z. The rock inscriptions of lower Nubia (Czechoslovak concession), 1974.
found: Caminos, R.A. The shrines and rock-inscriptions of Ibrim, 1968.
found: Desai, P.B. Select stone inscriptions of Andhra Pradesh, 1962.
found: Hill, B. Guide to Indian rock carvings of the Pacific Northwest coast, c1975.
found: Dowson, T.A. Rock engravings of Southern Africa, 1992.
found: Wilman, M. The rock-engravings of Griqualand West & Bechuanaland South Africa, 1933.
found: American Heritage dictionary of the English language, via WWW, Dec. 8, 2003(petroglyph: A carving or line drawing on rock, especially one made by prehistoric people)
found: MSN learning website, Dec. 8, 2003:dictionaries (petroglyph: prehistoric rock drawing: a prehistoric drawing done on rock)
found: Merriam-Webster dict., via WWW, Dec. 8, 2003(petroglyph: : a carving or inscription on a rock)
