Jack Dawson, Oiva Toikka: Glass and Design, Helsinki, 2007, p. 60 for a similar example
Kaisa Koivisto and Pekka Korvenmaa, eds., Glass from Finland in the Bischofberger Collection, exh. cat., Le Stanze del Vetro and Fondazione Giorgio Cini, Venice, 2015, pp. 371, 412 for a similar example