Thomas Vaughan, Oregon Historical Quarterly/Volume 63… (1962)
“ During these memorable years he participated in the British Company's success and control in the Pacific Northwest, witnessed the challenge of American trappers and traders by land and sea, the arrival of the first American missionaries and settlers in the Oregon Country, their eventual dominance and the Company's decline and departure. Like Chief Factor John McLoughlin, Roberts was among those Hudson's Bay and Puget Sound Agricultural Company officers who became American citizens rather than leave the region which had become their home and where they had families and interests. ”
