1769
The special effects shots of the attacking birds were completed at Walt Disney Studios by animator / technician , Ub Iwerks , who used the sodium vapor process ( " yellow screen " ) , which he had helped to develop .
 location: Walt Disney Studios; person: Ub Iwerks
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 location: Walt Disney Studios; person: Ub Iwerks