<prompt> Yakha inguqulo eyinkimbinkimbi yalesi sigwebo Umqulu wokuqala,The Economic Point of View , waphuma ngoDisemba 2009.  <response>: Yiqiniso, inguqulo eyinkimbinkimbi yomusho ithi Umqulu wokuqala,The Economic Point of View, waphuma ngoDisemba 2009, nomqulu wesibili,Market Theory and the Price System, ngoMeyi 2011. 