Cedergren B, Giles C M, Ikin E W
Vox Sang. 1976 Nov;31(5):344-55. doi: 10.1111/j.1423-0410.1976.tb04658.x.
Using the potent anti-Vel, Paul., a detailed study of the Vel blood group has been made in the Northern region of Sweden. Family studies have shown Vel to be independent of P1, though some association with P groups was detected since P2 was more frequent amongst Vel(-) than expected. The frequency of Vel(-) was 0.0006.
利用强效抗-Vel，保罗等人对瑞典北部地区的Vel血型进行了详细研究。家系研究表明，Vel与P1无关，不过由于在Vel阴性个体中P2出现的频率高于预期，因此发现它与P血型组存在一些关联。Vel阴性的频率为0.0006。
