Publisher Houghton Mifflin will offer four references books in applications that work with iPhones.According to Publishers Weekly magazine: “In the first move by a major American publisher to publish iPhone-ready (and friendly) reference material, Houghton Mifflin Harcourt has rolled out applications for four of its reference titles. The titles, which can be purchased in Apple’s App Store range in price from $29.99, for ‘The American Heritage Dictionary of the English Language,’Fourth Edition, to $8.99 for ‘Wall Street Words.’”

The fourth edition of the American Heritage dictionary has 2,074 pages and weighs about 7.5 pounds in book form. The app features photos, maps and sound (so users can hear pronunciations) and is the first time a publisher has made a dictionary of this size available on a handheld device.

Look for more reference material to be offered for iPhones in the coming months.