Jacqueline,
    Last I checked, NISO still had copies of Z39.44-1986, its standard
for Serials Holdings Statements available.  There is a companion
standard Z39.57-1989 Holdings Statements for Non-serial Items, which
you may or may not need.  NISO can be reached at (800) 282-NISO
or at www.niso.org.  A new standard, which will replace these two,
is in the works, but statements you build using Z39.44 and .57 will
remain valid under the new standard, Z39.71-199X.

Ellen Rappaport
Co-Chair of NISO Standards Committee SC AL, working on Z39.71-199x
Tech Services Librarian, Albany Law School Library, Albany NY
erapp@mail.als.edu