Perhaps you should try some spelling variations:
de covarianza » de varianza
abierta y » abierta de, abierta en
marco r » marco de
r 1886 » o 1886, r 1856, r 1881
ana _ » ana m, dna _, ana c
12 el » 2 el, 11 el, 10 el
1 30 » 1 20, 1 50, 1 3
y 12 » y 122, y 2, 1 12

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( Cabildo abiertas 1 30 de covarianza ana _ ) OR ( Cabildo abierta y 12 el marco r 1886 ))~".
• Adding a wildcard symbol may retrieve word variants: (( Cabildo abiertas 1 30 de covarianza ana _ ) OR ( Cabildo abierta y 12 el marco r 1886 ))*.