MANILA REPORTS MINDANAO TRUCE
Philippine Govt announces on Aug 14 that Moslem rebels in southern Mindanao, who fought under banner of Moro Liberation Front, had accepted cease fire; while Govt announcement did not disclose what concessions had been made by either side that would back up the cease fire, it says that 'modalities of autonomy and an internal force' in rebels' area would be discussed; spokesman for Pres Marcos comments; history of rebel insurgence in southern Mindanao noted; map (M)
