Mazeres, F ; Brinkmann, K ; Richter, M https://researchonline.ljmu.ac.uk/id/eprint/15444/1/Explicit%20achievement%20motive%20strength%20determines%20effort-related%20myocardial%20beta-adrenergic%20activity%20if%20task%20difficulty%20is%20unclear%20but%20not%20if%20task%20difficulty%20is%20clear.pdf.
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2021