Request for Information on Egon Schiele's SEMI-NUDE BLOND GIRL WITH BLUE SHIRT AND BLUE HEADBAND

We are trying to ascertain the following about the provenance given below, any information given would be helpful:

1.   According to Jane Kallir's catalogue raisonne Egon Schiele:  The Complete Works (Abrams 1998), this work was in an Antiquariat Steinbach sales catalogue in Vienna in 1960.   We have not been able to ascertain who put this work up for sale, whether it was sold, and if so, who bought it.

2.  We have not been able to ascertain the first name or the address of "Glowacki", the reported consignor of the artwork to Klipstein & Kornfeld for the 1963 auction.

3.  We have contacted Sotheby's and have been informed by Sotheby's counsel John Cahill that they are actively researching these questions.

Any information that can be provided on the pre-1963 provenance of this artwork would be greatly appreciated.

An excerpt from the Sotheby's catalog found here.
Impressionist & Modern Art Evening Sale


New York
5 May 2010, 7:00 PM
N08633

LOT 6 PROPERTY FROM A PRIVATE COLLECTION

EGON SCHIELE  1890 – 1918

BLONDER MÄDCHENHALBAKT MIT BLAUEM HEMD UND BLAUEM HAARBAND (SEMI-NUDE BLOND GIRL WITH BLUE SHIRT AND BLUE HEADBAND)

Signed Egon Schiele and dated 1913 (lower right)
Gouache, watercolor, and pencil on paper

18 7/8 by 12 5/8 in.
48 by 32 cm
Executed in 1913.

ESTIMATE 700,000 - 1,000,000 USD
PROVENANCE

Glowacki (sold: Klipstein &Kornfeld, Bern, May 11, 1963, lot 995)
Rudolf Leopold, Vienna
Serge Sabarsky, New York
Saidenberg Gallery, New York
Gift of the above to the present owner

EXHIBITION
Vienna, Antiquariat Steinbach, circa 1960, no. 4
London, Marlborough Fine Art, Egon Schiele: Paintings, Watercolors and Drawings, 1964, no. 64

LITERATURE
Jane Kallir, Egon Schiele, The Complete Works, New York, 1998, no. 1286, illustrated p. 498