How to read Superintendent of Documents "call" numbers (SuDoc)
SuDoc call numbers are designed specifically for government documents by the office of the Superintendent of Documents. SuDoc Numbers look different from other types of call numbers. They include letters, numbers, spaces, periods, and usually other punctuation such as slashes, colons, and often dashes.
Here is a typical SuDoc Number: TD 4.10/4:91-19
To read a SuDoc Number, start with the letters. They will represent which government agency the document came from. The letters are followed by a number, a period (not a decimal point), and more numbers. In the example above "4.10" is the number four followed by the whole number ten. When reading call numbers on shelf, find the letters, then the first number, then the next numbers (after the period), then the numbers that come after the slash, then any more numbers there may be.
Thanks to Jernigan Library at Texas A&M University in Kingsville for this information