Mas`ala fī `amal al-mutawassiṭayn wa-qismat zāwiya ma`lūma bi-thalāthat aqsām mutasāwiyya = Qismat al-zāwiya al-mustaqīmat al-khaṭṭayn bi-thalāthat aqsām mutasāwiyya - under second title - Paris (2457/45)