Per Year

 @book{cole1978mind,
    author = {Vygotsky, Lev Semyonovich},
    editor = {Michael Cole and Vera John-Steiner and Sylvia Scribner and Ellen Souberman},
    journal = {Mind in society the development of higher psychological processes},
    publisher = {Harvard University Press},
    subtitle = {Development of Higher Psychological Processes},
    title = {Mind in Society},
    year = 1978
} 

 @article{lamport-acmcomm21,
	Address = {New York, NY, USA},
	Author = {Lamport, Leslie},
	Doi = {10.1145/359545.359563},
	Issn = {0001-0782},
	Journal = {Communications of the ACM},
	Number = 7,
	Pages = {558--565},
	Publisher = {ACM},
	Title = {Time, Clocks, and the Ordering of Events in a Distributed System},
	Url = {http://portal.acm.org/citation.cfm?id=359563},
	Volume = 21,
	Year = 1978}
 

 @book{activitytheory-book78,
    author = {Vygotskiĭ, Lev Semenovich},
    booktitle = {Mind in Society: Development of Higher Psychological Processes},
    editor = {Cole, Michael and John-Steiner, Vera and Scribner, Sylvia and Souberman, Ellen},
    isbn = {978-0-674-57629-2},
    isbn10 = {0-674-57629-2},
    numpages = 176,
    publisher = {Harvard University Press},
    title = {Mind in Society: Development of Higher Psychological Processes},
    url = {http://www.hup.harvard.edu/catalog/VYGMIX.html},
    year = 1978
}