Chang, H.T. 1926. On the question of the existence of elephants and rhinoceros in North China in historical times. Bulletin of the Geological Society of China 5: 99-105. { copied = true; setTimeout(() => copied = false, 10000); }).catch(err => { console.error('Failed to copy:', err); }); " type="button" :class="copied ? 'bg-secondary border-secondary' : 'border-primary hover:bg-primary'" class="group lg:min-w-64 flex items-center justify-between gap-5 border border-solid px-5 py-2 cursor-pointer transition-colors"> PDF download available