SIGMUND WIRKNER IS RECORDED AT THE LENOX FACTORY FROM 1900 INTO THE 20'S. SEE DOROTHY ROBINSON AND BILL FEENY, THE OFFICIAL PRICE GUIDE TO AMERICAN POTTERY & PORCELAIN, ORLANDO, FL, 1980, P. 45, HERE THE AUTHOR NOTES, VERY FEW EXAMPLES ARE KNOWN AND HIS PORTRAIT PIECES ARE PARTICULARLY DESIRABLE. ALSO SEE PROPERTY FROM THE COLLECTION OF LENOX/GORHAM, CHRISTIE'S, NEW YORK, 20 APRIL 2006, LOT 336 FOR A SIMILAR PAIR BY WIRKNER.