I add this as an answer because it answered my question. After reading the thread I was pointed to, I didn't find it that enlightening. Then, after googling for some time, I found this link to be very clear: redlinels.com/2012/07/13/theres-with-plural-nouns I hope this helps someone else, too!

redlinels.com/2012/07/13/theres-with-plural-nouns

I add this as an answer because it answered my question. After reading the thread I was pointed to, I didn't find it that enlightening. Then, after googling for some time, I found this link to be very clear. I hope this helps someone else, too!