Simplex sigillum veri : Peano, Frege, and Peirce on the primitives of logicBellucci, Francesco; Moktefi, Amirouche; Pietarinen, Ahti-VeikkoHistory and philosophy of logic2018 / p. 80-95 : ill https://doi.org/10.1080/01445340.2017.1358414 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS