@article{AIHPA_1981__35_4_253_0,
     author = {Klainerman, S. and Sarnak, P.},
     title = {Explicit solutions of $\square u = 0$ on the {Friedmann-Robertson-Walker} space-times},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {253--257},
     publisher = {Gauthier-Villars},
     volume = {35},
     number = {4},
     year = {1981},
     mrnumber = {650132},
     zbl = {0499.58028},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1981__35_4_253_0/}
}