Poonja, Mahmood M. (1977). Termination of Treaties Owing to Fundamental Change of Circumstances (Clausula Rebus Sic Stantibus) (Juris Doctor dissertation). Charles University, Prague (Rawalpindi: Abbas Arts, 1982). OCLC41731249.
Poonja, Mahmood M. (1977). Termination of Treaties Owing to Fundamental Change of Circumstances (Clausula Rebus Sic Stantibus) (Juris Doctor dissertation). Charles University, Prague (Rawalpindi: Abbas Arts, 1982). OCLC41731249.: p. 13, citing De iure belli libri tres, lib. 111, cap. XIV.