"The Institutional and Scientific Schools of Free Religion", by Francis Abbot, in The Index, Vol. 2, No. 15, April 15, 1871, p. 115, middle column
Affirmation 41 in "Fifty Affirmations" by Frances Potter. Reprinted on page 407 of A Documentary History of Unitarian Universalism, Volume One: From the Beginning to 1899, (2017), edited by Dan McKanan, Skinner House Books, Boston
"Truths for the Times" by Frances Abbot, final page. Originally published in 1872, this version of "Truths for the Times" with the Notice page was apparently printed in 1892.
Browne, E. Janet, Charles Darwin: The Power of Place, Vol. 2 (1996), Princeton University Press, p. 392