(159865) Silvialonso = 2004 PX66
Silvia Alonso Perez (b. 1976), of La Laguna, Tenerife, was responsible
for teaching astrometry to many Spanish amateur astronomers. This was the
beginning of the Minor Planet Center's assignment of many new observatory
codes in Spain.
A complete set of naming citations of the numbered minor planets is available in the Dictionary of Minor Planet Names, edited by Lutz Schmadel.