Scientific Papers

(2015)  The Role of Ortho-Retronasal Olfaction in Mammalian Cortical Evolution, by, Timothy B. Rowe and Gordon M. Shepherd.  Journal of Comparative Neurology.  Early Edition DOI:10.1002/cne.23802.  Invited paper for special volume on Cortical Evolution.

(2014)  Endocranial anatomy of a new fossil porpoise (Odontoceti: Phocoenidae) from the Pliocene San Diego Formation of California, by Rachel Racicot and Timothy B. Rowe.  Journal of Palaeontology, 88(4): 652-663.

(2014)  Cranial anatomy of the Duchesnean primate Rooneyia viejaensis: New insights from high resolution computed tomography, by E. Christopher Kirk, Parham Daghighi, Thomas E. Macrini, Bhart-Anjan S. Bhullar, and Timothy B. Rowe   Journal of Human Evolution, 74:82-95.

(2013) Functional implications of ubiquitous semicircular non-orthogonality in mammals, by Jeri Cameron Berlin, E. Christopher Kirk, and Timothy B Rowe.  PLOS ONE PONE-D-13-32641R1 10.1371/journal.pone.0079585

(2013)  Evolutionary Origins of the Avian Brain, by Amy M. Balanoff, Gabe S. Bever, Timothy B. Rowe, and Mark A. Norell.  2013.  Nature 501 (7465): 93-96.  Doi: 10.1038/nature12424.

(2013) Lizards and snakes from the Terlingua local fauna (Late Campanian) Aguja Formation, Texas, with comments on the distribution of paracontemporaneous squamates throughout the Western Interior of North America, by Randall  Nydam, Timothy B. Rowe, and Richard L. Cifelli. Journal of Vertebrate Paleontology, 33(5):1081-1099.

(2012)  Respiratory and olfactory turbinal size in canid and arctoid carnivorans, by P. A.  Green, B. Van Valkenburgh, B. Pang, D. Bird, T. Rowe, and A. Curtis. Journal of Anatomy, 221: 609-621. doi:10.1111/j.1469-7580.2012.01570.x Supplemental material: Carnivorans on

(2012) The internal nasal skeleton of the bat Pteropus lylei (Chiroptera: Pteropodidae, by  Giannini, Norberto P., Thomas E. Macrini, John R. Wible, Timothy Rowe, and Nancy B. Simmons.  (2012) Annals of the Carnegie Museum of Natural History, vol 81 (1): 1-17.

(2012) Reassessment of the morphology and paleobiology of the therocephalian Tetracynodon darti (Therapsida), and the phylogenetic relationships of Baurioidea, by  Trond Sigurdsen, Adam K. Huttenlocker, Sean D. Modesto, Timothy B. Rowe, and Ross Damiani.  Journal of Vertebrate Paleontology. 32(5): 1113-1134.

(2012) Birds have paedomorphic dinosaur skulls, by Bhart-Anjan Bhullar, Jesús Marugán-Lobón, F. Racimo, Gabe S. Bever, Timothy Rowe, Mark Norell, and Arhat Abzhanov.  Nature 487: 223-226. doi:10.1038/nature11146

reviewed in the NY Times, May, 2012

(2011) Morphology and variation within the bony labyrinth of zhelestids (Mammalia, Eutheria) and other therian mammals, by Eric Ekdale and Timothy B. Rowe.  Journal of Vertebrate Paleontology, 31 (3): 658-675.  DOI: 10.1080/02724634.2011.55728

(2011) Fossil Evidence on Origin of the Mammalian Brain, by Timothy B. Rowe, Thomas E. Macrini, and Zhe-Xi Luo.  Science 332, 955-957.  DOI: 10.1126/science.120311>
Web Supplement on
Science Commentary on this article by R. Glen Northcutt
Science Supplemental Online Material

(2011) The Disappearing Third Dimension by Timothy B. Rowe and Lawrence R. Frank.   Science, 331: 712-714

Introduction to this Special Edition of Science on “Dealing with Data”

Web Supplement on

Web Supplement on

(2011) Dispersal and Diversity in the Earliest North American Sauropodomorph Dinosaurs, with a Description of a New Taxon, by  Timothy B. Rowe,  Hans-Dieter Sues, and Robert R. Reisz.  Proceedings B, Royal Society of London, 7 April, 2011, vol. 278 (no. 1708), 1044-1053, + 87 pp electronic supplemental data.
Web Supplement on Sarahsaurus aurifontanalis

(2010)  Cretaceous Extinctions: Multiple Causes, by David Archibald, William A.  Clemens, Kevin Padian, Timothy B. Rowe, Norman MacLeod, Paul M.  Barrett, Andrew Gale, Pat Holroyd, Hans-Dieter Sues, Nan C. Arens, John R.  Horner, Gregory P. Wilson, Mark B. Goodwin, Christopher A. Brochu, Donald L.  Lofgren, Surart H. Hurlbert, Joseph H. Hartman, David A. Eberth, Paul B. Wignall,  Philip J. Currie, Anne Weil, Guntupalli V. Prasad, Lowell Dingus, Vincent  Courtillot, Angela Milner, Andrew Milner, Sunil Bajpal, David Ward, and Ashok  Sahni.  Science, 328: 973.

(2009)  A Review of the Mongolian Cretaceous Dinosaur Saurornithoides (Troodontidae, Theropoda),  by Mark Norell, Peter J. Mackovicky, Gabe S. Bever, Amy M.Balanoff, James M. Clark, Rinchin Barsbold,  and Timothy Rowe.  American Museum Novitates, no 3654, 63 pp.Web Supplement on Saurornithoides mongoliensis

(2009)  Hindlimb Osteology and Distribution of Basal Dinosauromorphs from the Late Triassic of North America, by S. J. Nesbitt, R. B. Irmis,  W. G. Parker, N. D. Smith, A.H. Turner, and T. B. Rowe.   Journal of Vertebrate Paleontology, 29(12): 498-516.

(2008) Ontogenetic Sequence Analysis: Using Parsimony to Characterize Developmental Sequences and Sequence Polymorphism,  by Matthew W. Colbert and Timothy Rowe.   Journal of Experimental Zoology (Mol. Dev. Evol.) 310B:1-19.

(2008) The Oldest Platypus, and its Bearing on Divergence Timing of the Platypus and Echidna Clades, by Timothy B. Rowe, T. H. Rich,  P. Vickers-Rich, M. Springer, and M. O. Woodburne.   Proceedings National Academy of Sciences 105:1238-1242 + online supplementary information.Web Supplement on  Teinolophos trusleri

(2007)  Introduction by Timothy Rowe, to the digital re-publication of  Memoirs on the Extinct Wingless Birds of New Zealand,  with an appendix on those of England, Australia, Newfoundland,  Mauritius, and Rodriguez, by Sir Richard Owen (1879).

(2007)  Structural Extremes in a Cretaceous Dinosaur, by P. C. Sereno, J. A. Wilson,  L. A. Witmer, J. A. Whitlock, A. Maga, O. Ide, and Timothy B. Rowe.  PLoS ONE 2(11): e1230.Web Supplement on Nigersaurus taqueti

(2007) Osteological Description of an Embryonic Skeleton  of the Extinct Elephant Bird, Aepyornis (Palaeognathae, Ratitae), by Amy M. Balanoff and Timothy B. Rowe. Memoir 9, Society of Vertebrate Paleontology;  Journal of Vertebrate Paleontology, supplement to volume 27: 1-54,  plus supplementary CD-ROM.
Web Supplement on Aepyornis maximus

(2007)  Cranial Endocasts from a Growth Series of Monodelphis domestica (Didelphidae, Marsupialia): A Study of Individual and Ontogenetic Variation,  by Thomas E. Macrini, Timothy B. Rowe, and John VandeBerg. 2007.  Journal of Morphology, 268:844-865 (published online 11 July, 2007).Web Supplement on Monodelphis domestica

(2007)  Digital endocast of Pucadelphys andinus, a Paleocene metatherian,  by Thomas E. Macrini, Christian de Muizon, Richard L. Cifelli, and Timothy B. Rowe.  Journal of Vertebrate Paleontology 27: 99-107.Web Supplement on Pucadelphys andinus

(2006)  The presence of cleithra in the basal turtle Kayentachelys aprix,  by Walter G. Joyce, Farish A. Jenkins, Jr., and Timothy B. Rowe,   In: I. G. Danilov and J. F. Parham (eds.), Fossil Turtle Research, Volume 1, Russian Journal of Herpetology, 13 (Suppl.), pp. 93-103.Web Supplement on  coming soon

(2006)  Cranial Anatomy of the Spade-Headed Amphisbaenian Diplometapon zarudnyi (Squamata, Amphisbaenia) Based on High-Resolution X-ray Computed Tomography,  by Jessica A. Maisano, Maureen Kearney, and Timothy B. Rowe.   Journal of Morphology 267(1):70-102, posted on “early view” October 28, 2005.Web Supplement on Diplometapon zarudnyi
(2006)  A New Dromaeosaurid Theropod from Ukhaa Tolgod (Omnogov, Mongolia),  by Mark A. Norell, James M. Clark, Alan H. Turner, Peter J. Makovicky, Rinchen Barsbold,  and Timothy B. Rowe.  American Museum Novitates 3545: 1-51.Web Supplement on coming soon
(2005)  Comment on “Independent Origins of Middle Ear bones in Monotremes and Therians” by Gabe S. Bever, Timothy B. Rowe, Eirc G. Ekdale, Thomas E. Macrini,  Matthew W. Colbert, Amy M. Balanoff. Science, 309: 1492a.Web Supplement on Teinolophos trulseri
(2005) Cranial Endocast of the Cretaceous Theropod Dinosaur Acrocanthosaurus atokensis,  by Jonathan J. Franzosa, and Timothy B. Rowe.   Journal of Vertebrate Paleontology, 25(4): 859-864.Web Supplement on Acrocanthosaurus atokensis
(2005)  Anatomy of the Cranial Endocast of the bottlenose dolphin Tursiops truncatus based on HRXCT,  by Matthew W. Colbert, Rachel  Racicot, and Timothy B. Rowe.  Journal of Mammalian Evolution 12: 197-209.Web Supplement on Tursiops truncatus
(2005) Cranial Anatomy of the Extinct Worm-lizard Rhineura hatcherii (Squamata, Amphisbaenia) based on High-resolution X-ray Computed Tomography, by Maureen Kearney, Jessica. A. Maisano, and Timothy B. Rowe.  Journal of Morphology, 264: 1-33.
(2004)The Olfactory System of Tremacebus harringtoni(Platyrrhini, early Miocene, Sacanana, Argentina):  Implications for Activity Pattern,  by Richard F. Kay, V. M. Campbell, James B. Rossie, Matthew W. Colbert, and Timothy B. Rowe.  Anatomical Record Part B: The New Anatomist, 281:1157-1172.
Web Supplement on  Tremacebus harringtoni

(2004)  Respiratory Turbinates of Canids and Felids: A Quantitative Comparison,   by Blaire Van Valkenburgh, Jessica Theodor, Anthony Friscia, and Timothy B. Rowe. Journal of Zoology, London, 264: 1-13, + 87 pp electronic supplemental data.Web Supplement on various carnivorans

(2004)  Ceratosauria. by by R. S Tykoski and Timothy B. Rowe,  Pp. 47-70, In: The Dinosauria, D. Weishampel, P. Dodson, and H. Osmolska (eds.), 2nd edition, University of California Press.
Web Supplement on

(2004)  Chordate Phylogeny and Development. by Timothy B. Rowe,  Pp. 384 – 409, In: Assembling the Tree of Life (M. J. Donoghue and J. Cracraft, eds.), Oxford University Press, Oxford and New York.
Web Supplement on

(2004)  The Avian nature of the brain and inner ear of Archaeopteryx. by P. Dominguez-Alonso, A. C. Milner, M. J. Cookson, and Timothy B. Rowe,  Nature 430: 666-669.
Web Supplement on Archaeopteryx lithographica

See also commentary on this article: Inside the Oldest Bird Brain, by Lawrence M. Witmer, 2004.  Nature 430: 619-620.

(2004)  Anatomy the Old-Fashioned Way, by Timothy B. Rowe,  New York Times, Letter to the Editor.  March 30, 2004, p. D4.

(2004)  Structure and function of the horn shark (Heterodontus francisi) cranium through ontogeny: the development of a hard prey specialist. by Adam P. Summers, Richard A. Ketcham, and Timothy B. Rowe.    Journal of Morphology, 260:1-12.Web Supplement on Heterodontus francisi

(2003)  Neuroanatomy of flying reptiles and implications for flight, posture, and behavior. by Lawrence W.Witmer, Sankar Chatterjee, Jonathan Franzosa, and Timothy B. Rowe.    Nature, 425: 950-954.Web Supplement on Anhanguera santanae

(2003)  Geological applications of high-resolution X-ray computed tomography in petrology, meteoritics and palaeontology. by William D. Carlson, Timothy B. Rowe, Richard A. Ketcham, and Matthew W. Colbert.    Pp. 7-22, in F. Mees, R. Swennen, M. Van Geet, and P. Jacobs, Eds. Applications of X-ray computed tomography in the geosciences, 215, Geological Society, London.Web Supplement at UTCT

(2003)  Three-dimensional analysis of plant structure using high-resolution X-ray computed tomography. by W. H. Stuppy, J. A. Maisano, J.A., M. W. Colbert, P. J. Rudall, P.J., and Timothy B. Rowe.    Trends in Plant Science, 8, 2-6.Web Supplement on various plants

(2003)  New Information on Lethiscus stocki (Tetrapoda, Lepospondyli, Aistopoda) from High-Resolution X-ray Computed Tomography.. by Jason S. Anderson, Robert L. Carroll, and Timothy B. Rowe.    Canadian Journal of Earth Sciences, 40: 1071-1083.Web Supplement on coming soon

(2003)  Osteology and Relationships of Byronosaurus jaffei (Theropoda: Troodontidae).. by Peter J. Makovicky, Mark A. Norell, James M. Clark, and Timothy B. Rowe.    American Museum Novitates: Number 3402, pp. 1–32.Web Supplement on Byronosaurus jaffei

(2002) Calsoyasuchus valliceps, a new crocodyliform from the Early Jurassic Kayenta Formation of Arizona. by Ronald S. Tykoski, Timothy B. Rowe, Richard A. Ketcham, and Matthew W. Colbert.   Journal of Vertebrate Paleontology, 22(3): 593-611, with CD-ROM
Web Supplement on  Calsoyasuchus valliceps

(2002)  A furcula in the coelophysid theropod Syntarsus., by Ronald S. Tykoski, C. A. Forster, Timothy B. Rowe, Scot D. Sampson, and D. Munyikwa. Journal of Vertebrate Paleontology, 22(3): 728-733.Web Supplement on Syntarsus kayentakatae

(2002)  Cranial anatomy of Citipati osmolskae (Thgeropoda, Oviraptorosauria), and a reinterpretation of the holotype of Oviraptor philoceratops, by James M. Clark, Mark A. Norell, and Timothy B. Rowe,  American Museum Novitates 3364: 1-24.Web Supplement on Citipati osmolskae

(2002)  The osteoderms and palpebral in Lanthanotus borneensis (Squamata: Anguimorpha), by Jessical A. Maisano, Christopher J. Bell, Jacques A. Gauthier, and Timothy B. Rowe,  Journal of Herpetology 36(4):678-682.Web Supplement on Lanthanotus borneensis

(2002)  Dinosauria, by Timothy B. Rowe.  Encyclopedia of Evolution.  Oxford University Press, volume 1, pp. 263-268.Web Supplement on various non-avian dinosaurs

(2001)  The Archaeoraptor Forgery, by Timothy B. Rowe, Richard A. Ketcham, Camgbria Denison, Matthew W. Colbert, X. Xu, and Philip J. Currie. Nature, 410: 539-540.Web Supplement on coming soon

(2001)  Dinosaur with a heart of stone, by Timothy B. Rowe, Earle F. McBride, and Paul C. Sereno, Science 291: 783e.Web Supplement on coming soon

(1999)  At the roots of the mammalian tree, by Timothy B. Rowe. Nature 398:283-284.

(1999) Cranial morphology of Alligator and phylogeny of Alligatoroidae. by Timothy B. Rowe, Christopher A. Brochu, and Kyoko Kishi (eds.).  Memoir 6, Society of Vertebrate Paleontology.

The Visible Alligator Website
Web Supplement on  Alligator mississippiensis

(1999)  Introduction to Alligator: Digital Atlas of the Skull. , by Timothy B. Rowe, C. A. Brochu, and K. Kishi, Pp. 1-8 In: T. Rowe, C. A. Brochu, and K. Kishi.  Cranial morphology of Alligator and phylogeny of Alligatoroidae.   Memoir 6, Society of Vertebrate Paleontology.
The Visible Alligator Website
Web Supplement on  Alligator mississippiensis

(1999)  First Early Cretaceous Mammal from the Eastern Seaboard of the United States, by Richard L. Cifelli, Thomas R. Lipka, Charles R. Schaff, and  Timothy B. Rowe,  Journal of Vertebrate Paleontology 19(2): 199-203.
Web Supplement on  Arundelconodon hottoni

(1997)  Comparative rates of development in Monodelphis and Didelphis, by Timothy B. Rowe Science 275: 684.
(1997)  High-Resolution Computed Tomography: a breakthrough technology for Earth scientists, by Timothy B. Rowe, John Kappelman, William D. Carlson, Richard A. Ketcham, and Cambria Denison   Geotimes, 42(9): 23-27.
(1997)  Ceratorauria, by Timothy B. Rowe, Ronald S. Tykoski, and John Hutchinson Pp. 106-110 in: K. Padian and P. E. Currie (eds.)  Encylopedia of Dinosaurs.  New York, Acadedmic Press.


(1996)  Coevolution of the Mammalian Middle Ear and Neocortex, by Timothy B. Rowe Science 273: 651-654.
(1996)  Brain heterochrony and evolution of the mammalian middle ear by Timothy B. Rowe. Pp. 71-96  In: New Perspectives on the History of Life. M. Ghiselin and G. Pinna (eds.), California Academy of Sciences, Memoir 20.
(1996)  Fossil evidence for the origin of the marsupial pattern of tooth replacement, by Richard L. Cifelli, Timothy B. Rowe., W. Patrick Luckett, J. Banta, Reuben Reyes, and R. I. Howes.  Nature, 379:715-718.    .
(1994)  At the beginning: computer technology and the early history of mammals., by Timothy B. Rowe, and Ernest L. Lundelius. Discover, The  University of Texas at Austin, vol. 13(4): 22-28.
(1993)  Phylogenetic systematics and the early history of mammals, by Timothy B. Rowe.  Pp: 129-145 In: Mammalian Phylogeny (F. S. Szalay, M. J. Novacek, and M. C. McKenna, eds.), Springer-Verlag, New York.
(1993)  A complete skull of Chasmosaurus mariscalensis (Dinosauria, Ceratopsidae) from the Aguja Formation (Late Campanian) of west Texas, by C. A. Forster, Paul C. Sereno, T. W. Evans, and Timothy B. Rowe.  Journal of Vertebrate Paleontology, 13(2): 161-170.
(1992)  The Campanian Terlingua local fauna, with a summary of other vertebrates from the Aguja Formation, Trans-Pecos, Texas, by Timothy B. Rowe, Richard L. Cifelli, Thomas M. Lehman, and Anne Weil   Journal of Vertebrate Paleontology, 13(2): 161-170.
(1992)  Ancestry, paleontology, and definition of the name Mammalia, by Timothy B. Rowe, and Jacques A. Gauthier.   Systematic Biology, 41(3): 372-378.
(1990)  Ceratosauria, by Timothy B. Rowe, and Jacques A. Gauthier.   Pp. 151-168, In:  D. Weishampel, H. H. Osmolska, and P. Dodson (eds.), The Dinosauria.  First Edition. Los Angeles, University of California Press.

(1989)  A new species of the theropod dinosaur Syntarsus from the Early Jurassic Kayenta Formation of Arizona, by Timothy B. Rowe.   Journal of Vertebrate Paleontology, 9(2): 125-136
Web Supplement on  Syntarsus kayentakatae

(1989)  Origin and early evolution of theropods by Timothy B. Rowe p. 100-112 In: K. Padian (ed.), Dinosaurs.   Short Courses in Paleontology, No. 2.  Published by the  Paleontological Society and Department of Geological Sciences, University of Tennessee, Knoxville.
(1989)  Images for natural history by William Bottorff and Timothy B. Rowe Cadence, May, 1989: 105-108.
(1989)  Tetrapod phylogeny, by Jacques A. Gauthier, David Cannatella, Kevin de Queiroz, Arnold G. Kluge, and Timothy B. Rowe.    Pp. 337-353 In: The Hierarchy of Life [Nobel Symposium], B. Fernholm, H. Bremer, H. Jornvall (eds.), Nobel Symposium 70, Excerpta Medica, Amsterdam.
(1989)  Importance of fossils in phylogeny reconstruction, by Michael J. Donoghue, James Doyle, Jacques A. Gauthier, Arnold G. Kluge, and Timothy B. Rowe.    Annual Review of Ecology and Systematics, 20: 431-460.
(1988)  Definition, diagnosis and origin of Mammalia, by Timothy B. Rowe.    Journal of Vertebrate Paleontology, 8(3): 241-264.

(1988)  Amniote phylogeny and the importance of fossils, by Jacques A. Gauthier, Arnold G. Kluge, and Timothy B. Rowe.    Cladistics, 4: 105-209.
google scholar

(1988)  The early evolution of the Amniota, by Jacques A. Gauthier, Arnold G. Kluge, and Timothy B. Rowe.    Pp. 103-155 In: M. Benton (ed.) The Phylogeny and Classification of the Tetrapods,  Vol. 1: Amphibians, Reptiles and Birds.  Systematics Association Special Volume No. 35a.  Oxford, Clarendon Press.
(1987)  Definition and diagnosis in the phylogenetic system, by Timothy B. Rowe.    Systematic Zoology, 36(2): 208-211.
(1987)  Homology and evolution of the deep dorsal thigh musculature in birds and other Reptilia, by Timothy B. Rowe.    Journal of Morphology, 198: 327-346.
(1986)  The hand of Anteosaurus magnificus (Therapsida, Dinocephalia) and Its bearing on the origin of the mammalian manual phalangeal formula, by Timothy B. Rowe and Juri van den Heever.    South African Journal of Science, 82(11): 641-645.
(1986)  Osteological Diagnosis of Mammalia, L. 1758, and its Relationship to Extinct Synapsida, by Timothy B. Rowe.    PhD Dissertation, Department of Paleontology, University of California, Berkeley, 446pp.
(1982)  The instrumental role of paleontology in the funding and development of a major new natural history museum, by Timothy B. Rowe, Richard L. Cifelli, and Barry Kues.    Journal of Paleontology, 56(4): 839-842.
(1981)  On the occurrence of Pentaceratops (Reptilia, Ceratopsia), with a description of its frill by Timothy B. Rowe, Edwin H. Colbert, and J. Dale Nations.    Pp. 29-48 In: S. Lucas, J. K. Rigby, and B. Kues (eds.), Advances in San Juan Basin Paleontology.  Albuquerque, University of New Mexico Press.
(1980)  The morphology, affinities, and age of the dicynodont reptile Geikia elginensis, by Timothy B. Rowe.    Pp. 269-294 In: L. L. Jacobs (ed.), Aspects of Vertebrate History: Essays in Honor of Dr. Edwin Harris Colbert.  Flagstaff, Museum of Northern Arizona Press.
(1979)  Placerias: an unusual reptile from the Chinle Formation. by Timothy B. Rowe.    Plateau, 51(4): 30-32.


(1998) The Mistaken Extinction – Dinosaur Evolution and the Origin of Birds.

By Lowell Dingus and Timothy Rowe. New York, W. H. Freeman & Co., 322 pp.   ISBN 0-7167-2944-X, ISBN 0-7167-3227-0 (academic version).


(1999) Alligator: Digital Atlas of the Skull, by Timothy B. Rowe, C. A. Brochu, K. Kishi, M. Colbert, J. W. Merck, Jr., E. Saglamer, and S. Warren. 1999.  Interactive Multimedia on CD-ROM for Macintosh and PC computers.  in: T. Rowe, C. A. Brochu, and K. Kishi (eds.). Cranial Morphology of Alligator and Phylogeny of Alligatoroidae. Memoir 6, Society of Vertebrate Paleontology.

The Visible Alligator Website Alligator mississippiensis
(1995) Thrinaxodon: Digital Atlas of the Skull, by Timothy Rowe, William Carlson, and William Bottorff. 1995.   CD-ROM for Windows and Macintosh platforms, Second Edition, University of Texas Press, 547 megabytes.

(1993) Thrinaxodon: Digital Atlas of the Skull, by Timothy Rowe, William Carlson, and William Bottorff. 1993.   CD-ROM for MS-DOS platform, First Edition, University of Texas Press, 623 megabytes.

External Web Sites