Refrigerants ranked by Partial Order Theory. - Guillermo Restrepo; Monika Weckert; Rainer Brüggemann; Silke Gerstmann; Hartmut Frank (EnviroInfo (2), 2007)

Hasse Diagram Technique - A Useful Tool for Life Cycle Assessment of Refrigerants. - Monika Weckert; Guillermo Restrepo; Silke Gerstmann; Hartmut Frank (EnviroInfo (2), 2007)

Ranking of Refrigerants by Different Assessment Methods. - Monika Weckert; Guillermo Restrepo; Silke Gerstmann; Hartmut Frank (EnviroInfo, 2008)