...—Orlando Furioso must be referred to for the history of thisenchanted and invulnerable headpiece, which is several times alluded to in DonQuixote... 
Miguel de Cervantes Saavedra 「The History of Don Quixote de la Mancha」
...He also gave some elephants' tusks, worth 30 Pounds, for another medicine which was to make him invulnerable to musket balls...
David Livingstone 「Missionary Travels and Researches in South Africa」
...A short time afterwards, another band approaching, one of the men was shot, who turned out to be a magician, and was till then thought invulnerable...
W.H.G. Kingston 「Great African Travellers」
...In addition, the chickens were raised in wirecages above the ground where they were nearly invulnerable topredation...
Terry A. Vaughan 「Mammals of the San Gabriel Mountains of California」
...One would think they were invulnerable, yetthe glyptodon and the chlamydothere, with many other equally wellprotected creatures, have long ago disappeared from the earth, but howand why nobody knows...
Royal Dixon 「The Human Side of Animals」
...They burrow with greatrapidity and when rolled up, after the manner of the hedgehog,are invulnerable to their ordinary enemies...
Various 「Natural History in Anecdote」
...Thus he was invulnerable inbattle...
Sir James George Frazer 「The Golden Bough」
...We have seen that in the tales the hero, as a preparation forbattle, sometimes removes his soul from his body, in order that hisbody may be invulnerable and immortal in the combat...
Sir James George Frazer 「The Golden Bough」
...He himself was invulnerable as he appeared before these monsters, for the reason that he always buried his veins near a tree before attacking them...
Edward S. Curtis 「The North American Indian」
...Having undergone thesedreadful ordeals, they were considered as invulnerable, andbelieved that the arrows of their enemies could no longer harmthem...
Sir James George Frazer 「Balder The Beautiful, Vol. I.」
...Once the borer hasleft it, it is invulnerable no longer...
Various 「Astounding Stories, May, 1931」
...Hundreds of airplanesare disintegrated before they discoverthat the enemy is invulnerable...
Various 「Astounding Stories of Super-Science, December 1930」
...The Mercutians are not invulnerable...
Nat Schachner 「Slaves of Mercury」
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