Help, new shoes. Licensed by Birkenstock.?

i bought these shoes
http://www.amazon.com/Newalk-Licensed-Birkenstock-Black-Sandal/dp/B001FXOFMU/ref=pd_ybh_4?pf_rd_p=280800601&pf_rd_s=center-2&pf_rd_t=1501&pf_rd_i=ybh&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0GRVFZHT1NYAGWYFRRVZ
and they came today.

and it says that their licensed by Birkenstock.
What does that mean?