If you are trying to find citations for an artist identified only by a monogram, symbol, or nickname, there are some special functions built into the Index of Print Catalogues Raisonné (IPCR) of which you should be aware.
Unidentified artists in IPCR are divided into four groups: Monogrammists, Masters of, Workshop of, and Symbols. You can bring up long pick-lists of such artists by loading one of the following words into the Search Box: "Monogrammist" (or even just M-o-n-o); "Master"; "Workshop"; or "Monogram Symbol"
You can then select individual names from the alphabetical pick-lists in order to view citations. For artists known only by Symbol, you can also go to the Thumbnails of Symbols page and view symbols for which citations exist.
If you have more information about the artist that you are looking for, you can easily narrow your search. If you are trying to locate a catalogue raisonné for Monogrammist E.S., you can simply search on the letters which make up the monogram by entering "E.S." (or, without the punctuation, "ES") into the search box.
Artists known only by dates or by nicknames, such as Master of 1515 or Master of the Playing Cards, can be found by searching on keywords from the nickname -- "1515" or "playing cards".
Many, but not all, monogrammists in IPCR are also identified by their Nagler number. This number refers to the multi-volume reference work, Die Monogrammisten und diejenigen bekannten und unbekannten Künstler aller Schulen welche sich zur Bezeichnung ihrer Werke eines figurlichen Zeichens, der Initialen des Namens, der Abbreviatur desselben etc. bedient haben . . . mit den raisonnirenden Verzeichnissen der Werke anonymer Meister, deren Zeichen gegeben sind, und der Hinweisung auf die mit Monogrammen oder Initialen bezeichneten Produkte bekannter Künstler by Georg Kaspar Nagler (et al.), (Munich: G. Franz, 1858-1879, reprinted 1919 and 1966). When a Nagler number is known for a monogrammist it will appear as an alias to the main entry.
In order to view all of the Nagler numbers in IPCR, enter the name "Nagler" in the search box. This will result in a long pick-list, arranged by volume and ID number, a portion of which is illustrated here:
(Nagler, Mon., I, no. 0101) Monogrammist A.A. (fl. 1500-1550), German
(Nagler, Mon., I, no. 0108) Monogrammist A.A. (fl. c.1526), Italian
(Nagler, Mon., I, no. 0322) Monogrammist A.C.H. (fl. before 1550), German
(Nagler, Mon., I, no. 0525) Monogrammist A.F. (fl. c.1500), Italian
(Nagler, Mon., I, no. 0613) Gerbel, Anton (fl. c.1470-1490), German
(Nagler, Mon., I, no. 0677) Monogrammist A.H. (fl. c.1550), Italian
In the list above, there are two "A.A." monogrammists. The first will be the particular monogram "A.A." reproduced and discussed by Nagler as number 0101 in volume I, and the second will be the "A.A." monogram discussed by Nagler as number 0108, in the same volume.
All artists known only by monogram, or identified as "Master of" or "Workshop of" are usually affiliated with a series of aliases. Such aliases are designed to facilitate searching, so that a user can simply enter "CH" to locate Monogrammist C.H., for example. Also, the Nagler number will appear as an alias to help identify common monograms:
Monogrammist C.H. fl. c.1515 German
Alias or alternative spelling: Monogrammist CH; CH; C.H.; Nagler, Mon., II, no. 0113
Additionally, many IPCR entries may have aliases reflecting scholarly arguments (either past or ongoing) which attempt to establish a more concrete identify for the artist. For example:
Master of the DIE b. c.1512, fl. 1533 Italian
Alias or alternative spelling: Vincidor, Tommaso di Andrea, Monogrammist B.; B.; B; Nagler, Mon. I, no. 1563
The appearance of these sort of aliases is meant to provide the researcher with all names associated with the monogram, symbol, or nickname.
Finally, a monogram may itself serve as an alias to an identified artist.
Palombo, Ascanio fl. c.1555 Italian
Alias or alternative spelling: Monogrammist A.P.; Monogrammist AP; AP; A.P.; Nagler, Mon., I, no. 1109;
This ensures that scholarship associated with the monogram is linked to the accepted artist.
For more information on using and searching on aliases and alternative names, see the What is an Alias or Alternative Name? page.