Esser, R. V. (1990). Between spheres: 30 march 1990-9 april 1990, National Museum of Fine Arts, Valletta, Malta / National Museum of Fine Arts, Valletta. [Verlag nicht ermittelbar].
Chicago-referens (17:e uppl.)Esser, Raniel Veronika. Between Spheres: 30 March 1990-9 April 1990, National Museum of Fine Arts, Valletta, Malta / National Museum of Fine Arts, Valletta. Valletta: [Verlag nicht ermittelbar], 1990.
MLA-referens (8:e uppl.)Esser, Raniel Veronika. Between Spheres: 30 March 1990-9 April 1990, National Museum of Fine Arts, Valletta, Malta / National Museum of Fine Arts, Valletta. [Verlag nicht ermittelbar], 1990.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.