The Princeton encyclopedia of classical sites on Delphi (via the Perseus Project). Text by G. Roux.
The Princeton Encyclopedia of Classical Sites, edited by Richard Stillwell.
The Temple of Apollo at Didyma . Reliable information with an architectural slant (includes a site plan), from James Grout's Encyclopedia Romana, an eclectic florilegium of articles on Rome and the Roman world (see the site map or the indexfor an idea of the contents).
Suda: Branchidae. (trans. Joseph McAlhany). Entry sympathetic to Alexander's destruction.
Bible places presents some attractive photos, decent text and a good list of links to mostly tourism-related websites.
Places of Peace and Power. Nice picture.
Wikipedia: Didyma. A "stub" or minimal entry; soon modern "pagans" will take this over and fill it with nonsense about the Mother Goddess.
Travelogue with good photographs by Fritz and Marie Schneider.
Photos of Didyma, fifty-three in number.
Dick Osseman's photos of Didyma. Exceptional.