AIDES DENY NIXON APPROVED CHARGE
Spokesmen for Pres Nixon try again on June 28 to dissociate Pres from any personal involvement in or approval of document submitted by White House to Sen Watergate com June 27 which labeled J W Dean 3d 'principal author of pol and const crisis Watergate now epitomizes' and accuses Dean of master-minding unsuccessful cover-up of Watergate burglary; document was prepared by Pres's special counsel, J F Buzhardt Jr; in related matter, deputy press sec G L Warren says Nixon will not accept invitation or subpoena to appear before Sen com; says 'we feel Pres should not testify' and 'subpoena...would be const inappropriate'