For three vases:
Colleen Sullivan, Chicago
Sotheby's, New York, "A Mid-Century Eye: The Collection of Colleen Sullivan," September 21, 2011, lot 20
For one vase:
Bonhams, Los Angeles, "20th Century Decorative Arts," October 16, 2011, lot 5200
Ulf Hård af Segerstad, Scandinavian Design, London, 1961, p. 49 for a similar example