JAKARTA (April 6)—Indonesia has agreed to join Thailand and Malaysia April 28-30 to discuss formation of a group to limit sales of natural rubber supplies in an effort to raise low prices, according to news reports. Reuters quoted Yusuf Kalla, Indonesian trade and industry minister, as saying he thought such a pact was "a good idea," but that Indonesia still is undecided as to whether it should join. Thailand, Indonesia and Malaysia account for more than 80 percent of the world´s NR production. Meanwhile, NR prices are up slightly across the board, because of the wintering of rubber trees and rubber buyers covering shortfalls. The price of Standard Indonesian Rubber 20 was 33 3/4 cents per pound on a spot basis in Norfolk, Va., on April 5.