[web2py] How to get a dropdown in self referencing table, create form?

[Edward Shave]

I have defined the following self referencing table.....

db.define_table(
    'account',
    Field('name'),
    Field('asset','boolean', default=False),
*    Field('transfer','reference account'),*
    format = '%(name)s',
    singular = 'Account',
    plural = 'Accounts',
    )

....How to get a drop down widget in create form for self referencing field?

I have seen talk of [represent], but need an example,

Any help will be much appreciated.

Ed