The upcoming Punjab Vidhan Sabha assembly start September 18 will have four sittings.According to the uncertain programme issued by the Vidhan Sabha secretary on Wednesday, the House will get together on September 18 afternoon for obituary references.While September 19 and 20 would be holidays, the House will meet in the afternoon on September 21 for legislative business and on September 22 morning for legislative business. September 23 will be a holiday.