[Bioperl-l] how to parse the GenPept sequence object to get the 'DBSOURCE' field

[Leonardo Kenji Shikida]

does anyone know how to parse the GenPept sequence object to get the 'DBSOURCE' field?

e.g. human.protein.gpff

LOCUS       NP_000358                245 aa            linear   PRI 31-OCT-2000
DEFINITION  thiopurine S-methyltransferase [Homo sapiens].
ACCESSION   NP_000358
VERSION     NP_000358.1  GI:4507653
DBSOURCE    REFSEQ: accession NM_000367.1  <<==
KEYWORDS    .
SOURCE      Homo sapiens (human)

I found no answer reading the docs, and there is the same unanswered question in this list archives at

http://bioperl.org/pipermail/bioperl-l/2003-June/012438.html

thanks in advance

K.