Silvia Bonettini Emanuele Galligani Valeria Ruggiero Inner solvers for interior point methods for large scale nonlinear programming. 1-34 2007 37 Comput. Optim. Appl. 1 https://doi.org/10.1007/s10589-007-9012-5 db/journals/coap/coap37.html#BonettiniGR07