From Google translate:

Translations of token

ένδειξη indication, clue, token, index, denotation, clew
σημείο point, sign, spot, place, mark, token
τεκμήριο presumption, token, inference
κέρμα coin, token
ειδικό νόμισμα token

Now, please see:

http://www.minddisorders.com/Py-Z/Token-economy-system.html


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Note added at 24 mins (2017-04-28 11:34:03 GMT)
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See the 2nd definition of 'token' in this reference:

http://www.wordreference.com/engr/token


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Note added at 32 mins (2017-04-28 11:41:52 GMT)
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Now see:

http://www.sciencedirect.com/science/article/pii/00057967759...

https://www.ncbi.nlm.nih.gov/pubmed/1104460

http://psycnet.apa.org/index.cfm?fa=buy.optionToBuy&id=1974-...

Results indicated that securing the early release through intensive token economy treatment of younger patients and patients who have been hospitalized for ...
https://books.google.co.uk/books?id=QulFBQAAQBAJ&pg=PA45&lpg...


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Note added at 47 mins (2017-04-28 11:56:51 GMT)
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And these:

http://psychology.wikia.com/wiki/Token_economy_programs

https://getrevising.co.uk/revision-notes/token_economy

https://www.researchgate.net/publication/256126815_Selecting...