Talvez deva tentar algumas variações de ortografia:
mongolia case » mongolian cases (Expandir a Pesquisa), mongolia past (Expandir a Pesquisa), mongolia causal (Expandir a Pesquisa)
east mongolia » east mongol (Expandir a Pesquisa), west mongolia (Expandir a Pesquisa), eastern mongolia (Expandir a Pesquisa)
camp can » clamp can (Expandir a Pesquisa), camp ca (Expandir a Pesquisa), amp can (Expandir a Pesquisa)
case now » cases now (Expandir a Pesquisa), case non (Expandir a Pesquisa), case new (Expandir a Pesquisa)
ac camp » a camp (Expandir a Pesquisa), c camp (Expandir a Pesquisa), amp camp (Expandir a Pesquisa)
can now » can non (Expandir a Pesquisa), can new (Expandir a Pesquisa), can ngoc (Expandir a Pesquisa)
m nucl » 3 nucl (Expandir a Pesquisa), m null (Expandir a Pesquisa)
j east » _ east (Expandir a Pesquisa), a east (Expandir a Pesquisa), j easton (Expandir a Pesquisa)
j ac » j a (Expandir a Pesquisa), j c (Expandir a Pesquisa), j al (Expandir a Pesquisa)

You can also try:

• Europeana
• Digital Public Library of America
• CORE

Pode obter mais resultados ajustando a pesquisa.

• "As palabras AND, OR e NOT podem gerar pesquisas incorrectas; tente utilizar aspas": "(( j ac camp can now ) OR ((( m nucl clamp _ noh ) OR ( j east mongolia case now ))))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( j ac camp can now ) OR ((( m nucl clamp _ noh ) OR ( j east mongolia case now ))))*.