@article{6df42361bc4c454bacc2231603da6be9,
title = "Gratitude for Help among Adult Friends and Siblings",
keywords = "gratitude, helping behavior, friendship, siblings, relationship closeness, SEX-DIFFERENCES, BIOBEHAVIORAL RESPONSES, RECIPROCAL ALTRUISM, TRADE-OFFS, EVOLUTION, KIN, COOPERATION, EXCHANGE, BEHAVIOR, RELATEDNESS, 515 Psychology, 5141 Sociology, 5142 Social policy",
author = "Anna Rotkirch and Minna Lyons and Tamas David-Barrett and Markus Jokela",
year = "2014",
language = "English",
volume = "12",
pages = "673--686",
journal = "Evolutionary Psychology",
issn = "1474-7049",
publisher = "Human Nature Review",
number = "4",
}