https://link.springer.com/article/10.1007/s11229-018-1814-8
https://link.springer.com/epdf/10.1007/s11229-018-1814-8?author_access_token=7M3Zz0Hm453gyczgdzpY-Pe4RwlQNchNByi7wbcMAY7RFgABR1_AO4zxVgEbcGQTMEDDaoIk4cZ5AsHdPFozoqKYokhsVw7QuAYKR2EtSK0hJFfk0l7wrYvgSkvoxA724Ok_qWJNACNhtK0QMLvlxA%3D%3D