@article{RSMUP_1987__77__161_0,
     author = {Dimitri\'c, Radoslav},
     title = {Chains of free modules and construction of $x$-free modules},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {161--176},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {77},
     year = {1987},
     mrnumber = {904618},
     zbl = {0629.13006},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_1987__77__161_0/}
}