29060
In 1939 he became acquainted with Immanuel Velikovsky and became a lifelong friend , informal literary advisor , mentor , and advocate .
 Immanuel Velikovsky
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Immanuel Velikovsky