10508
In his first season with the club , he managed to save the club that was staring relegation in the face after the disastrous reigns of his two predecessors , Christian Gross and Jens Keller , ended in the last quarter of 2010 .
 Christian Gross, Jens Keller
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:
 Christian Gross, Jens Keller