citing some arcane study may not have the impact you are looking for.
cost benefit analysis is what a company wants to see
so you argument should be
cost: 0 , monitor was discarded
benefit 1: "This has made it much easier to do my job"
benefit 2: if work is easier, i should be able to do more of it in the same time frame
argument 1: even if its only a 1% increase in productivity it is worth it, because the monitor cost 0
argument 2: this is also a perfect oportunity to study the benefits of addtional monitors, and possibly decide if purchasing them are worth it also
argument 3: CSI has tons of monitors, and they always get the job done in less than an hour
argument 4: with 2 monitors i can actually do work, while waiting for a group in World of Warcraft