References
Herman Ruge Jervell
with Gjelsvik Olav (1994). Preface. Synthese, 98 (1), 1-2. https://doi.org/10.1007/BF01064022.
(1987). Reasoning in trees. In D. G. Skordev (ed.) Mathematical logic and its applications (pp. 125-135). Dordrecht: Springer.