was enroute from Estevan to Lloydminster at FL 200 when the pilot advised ATC that the right engine had quit momentarily about 45 miles southeast of Regina. The engine had apparently returned to normal operation, but the pilot decided to divert to Regina to have the engine checked out. ERS was called out and the a/c landed safely at 0232Z. No other flights were inconvenienced. UPDATE As the pilot levelled the a/c at FL 210 and turned off the auxiliary boost pumps, the right engine lost power. Several seconds later, the engine regained power without the pilot having intervened. The pilot diverted the a/c to Regina, where maintenance found that the engine driven fuel pump for the right engine was putting out only 13 psi when 18 psi is normal. The pump was overhauled and the problem has not recurred.