Jozsef Abaffy Marida Bertocchi Adriana Gnudi Extensions of the Ho and Lee interest-rate model to the multinomial case. 154-169 2005 163 European Journal of Operational Research 1 http://dx.doi.org/10.1016/j.ejor.2004.01.005 db/journals/eor/eor163.html#AbaffyBG05