Guides > Selecting and Viewing Items > Date Formats
We recently implemented the Library of Congress' Extended Date Time Format as the date standard for metadata records in The Portal to Texas History, the UNT Digital Library, and The Gateway to Oklahoma History. Although this involves some strict "behind-the-scenes" formatting, we transform the dates for display on our web sites. In most cases, item records will show dates written out in words such as:
July 14, 1822
However, some dates include symbols to show that they are approximate, uncertain, etc. If we think that the date displayed in the item record will be confusing, we add an information icon that brings you to this page for an explanation of the symbols:
u (letter "u") - A "u" takes the place of an unknown digit if only part of the date is known or is legible on the item: 191u represents the "1910s" and 1887-03-1u is March 1887 on an unknown day between the 10th and the 19th.
~ (tilde) - The tilde notes that the date is "approximate": 1893~ is "approximately 1893" (or "circa 1893").
/ (forward slash) - A forward slash separates dates in a range: 1851/1863-08 is "sometime between 1851 and August 1863" (or "1851 through August 1863").
? (question mark) - A question mark after a date notes that it may not be correct: 1758? means "this item was probably created/published in 1758, but the date is not certain."
[ ] (square brackets) - Square brackets are used by some institutions (such as libraries) to note that the information was not found in the item:  means that an item was written/published/created in 1902, but does not have a date stamped or printed on it.