404. That’s an error.

The requested URL /bookmarks/mark?op=add&bkmk=http%3A//physrev.physiology.org/content/43/4/529&title=Gastric%20Intrinsic%20Factor%20and%20its%20Function%20in%20the%20Metabolism%20of%20Vitamin%20B12 was not found on this server. That’s all we know.