@misc{cryptoeprint:2002:050,
    author = {Jaume Martí-Farré and Carles Padró},
    title = {Secret sharing schemes with three or four minimal qualified subsets},
    howpublished = {Cryptology ePrint Archive, Report 2002/050},
    year = {2002},
    url = {http://eprint.iacr.org/2002/050},
}