Kaula Island - good info, from a historical perspective.
Ka'ula Island - brief info with a good pic.
Kaula Volcano - very brief info on the volcano that once erupted there.
NGS Project - NW Hawaiian Islands - Kaula Island - 2 photos from 1961.
Niihau Island - small topographical map on this page.
Ululoa Productions - Lei‘ohu Ryder's tribute to the island in both Hawai'ian and English.