Referenced In

The Travels of Marco Polo
by Marco Polo, da Pisa Rusticiano

"… on the north bank of the canal, nearly under the 35th degree of latitude, and a short distance west of Kai-fung fu."

The Travels of Marco Polo
by Marco Polo, da Pisa Rusticiano

"At the siege of Kai-fung fu near the Hwang-Ho, the latest capital of the Kin Emperors, in 1232, the Mongol General Subutai used his engines."