http://biblioteca.ubl.ac.cr/cgi-bin/koha/opac-search.pl?q=ccl=an%3A%2220903%22&format=rss2 3 0 50 ISBN http://biblioteca.ubl.ac.cr/cgi-bin/koha/opac-detail.pl?biblionumber=17255 By Hillers, Delbert R.. Philadelphia, Pa. : Fortress, 1984 . 116 p. ; 24 cm.

]]> http://biblioteca.ubl.ac.cr/cgi-bin/koha/opac-detail.pl?biblionumber=17255 ISBN http://biblioteca.ubl.ac.cr/cgi-bin/koha/opac-detail.pl?biblionumber=16573 By Hillers, Delbert R.. Garden City, N.Y. : Doubleday, 1972 . xii, 116 p. ; 24 cm..

]]> http://biblioteca.ubl.ac.cr/cgi-bin/koha/opac-detail.pl?biblionumber=16573 ISBN 0801810116 http://biblioteca.ubl.ac.cr/cgi-bin/koha/opac-detail.pl?biblionumber=30807 By Hillers, Delbert R.. Baltimore : Johns Hopkins University, 1982 . 194 p. ; 21 cm.. 0801810116

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