{"word_count": 582, "character_count": 3692}
One of the main services that we have planed using automatic annotation is to provide a unique identifier such as DOI (Digital Object Identifier) to each reference. DOI is assigned by CrossRef, the registration agency of the International DOI Foundation (IDF). We use the CrossRef's query service that allows us to extract DOI with some basic information about a target digital document.To submit queries into CrossRef from our system, we need a registered user id. However, CrossRef also provides several guest query interfaces without inscription on the site. So before applying the service in our system, we analyzed the guest query interfaces. First, we need to have at least title and author name, especially surname of first author. If we enter full name, the system does not find an item. Second, the reference string parsing service in the site does not always work. For example, with the reference string, [WACQUANT, Loïc, "Deadly Symbiosis: When Ghetto and Prison Meet and Mesh", in Punishment and Society 3, 2000, pp. 95-134.], we could not find the DOI even though it actually exists. Third, when we add metadata besides the basic information for searching, it should be exact. If not the system cannot find DOI even though it could by just submitting basic information (title and author). Fourth, title with several beginning words works well.Finally, we decided to use xml queries with some beginning words of title and surname of first author. For each bibliographical reference in test data of corpus 1, these two items are extracted from the automatic annotation result. As a result, among 215 references 22 are revealed as having a DOI. Interestingly, 10 DOIs over 22 have not been discovered using the auto parsing service of CrossRef at the guest query interface (marked with '***' in  the following examples). We sampled 6 references that reflect the diversity of form.(Reference string  | automatically extracted items | found DOI | particularity)CHAUVEAU, J-P, DOZON J-P. et RICHARD J., 1981, Histoires de riz, histoires d’igname. Le cas de la moyenne Côte d’Ivoire, Africa, 51 (2), 621-658. | First author :   CHAUVEAU  Start of title :   Histoires de riz | DOI : 10.2307/1158830 |JOHNSTON-FELLER, R., Color Science in the Examination of Museum Objects. Nondestructive Procedures, Los Angeles, The Getty Conservation Institute, 2001.  | First author :   JOHNSTON-FELLER    Start of title :   Color Science in the Examination of Museum Objects | DOI : 10.1002/(ISSN)1520-6378 | ***NO DOI when AUTO PARSING in the siteORGANSKI Kenneth, 1958, World Politics, New York, Knopf. | First author :   ORGANSKI     Start of title :   World Politics | DOI : 10.2307/1338221 | ***WRONG DOI when AUTO PARSING in the siteKRUEGER Dirk &#38;amp; Fabrizio PERRI, “Does Income Inequality Lead to Consumption Inequality? Evidence and Theory”, Review of Economic Studies, 73 (1), 2006. | First author :   KRUEGER      Start of title :   Does Income Inequality Lead to Consumption Inequality | DOI : 10.1111/roes.2006.73.issue-1 |Halperin David M., Winkler John J. et Zeitlin Froma I. (éd.) (1990), Before Sexuality. The Construction of Erotic Experience in the Ancient World, Princeton. | First author :   Halperin    Start of title :   Before Sexuality | DOI : 10.1080/03612759.1991.9949408 | ***NO DOI when AUTO PARSING in the siteVeyne Paul (1981), «L’homosexualité à Rome», Histoire 30, p. 71-78 (= légèrement augmenté, « L’homosexualité à Rome », Communication 35, 1982, p. 26-33), réédité dans Duby G. (éd.), Amour et sexualité en Occident (1991), Paris, Seuil, p. 69-77). | First author :   Veyne    Start of title :   L’homosexualité à Rome | DOI : 10.3406/comm.1982.1519 | &#160;