De Vinne, Theodore Low (1901). The Practice of Typography; correct composition; a treatise on spelling, abbreviations, the compounding and division of words, the proper use of figures and numerals . The Century Company. p. 142–143 – via Wikisource. [scan ] https://en.wikisource.org/wiki/Index:The_practice_of_typography;_correct_composition;_a_treatise_on_spelling,_abbreviations,_the_compounding_and_division_of_words,_the_proper_use_of_figures_and_numerals_by_De_Vinne,_Theodore_Low,_1828-1914.djvu