Sorry: This link is clearer. http://argentina.travisa.com
PS: You mentioned a receipt for en e-tkt? Do you mean proof of purchase of an e-tkt? That is enough evidence of a return flight out of Argentina- but with regards to Buquebus: With a one way boat ticket to Uruguay as your evidence on...
You could contact the Airline directly as they should have information re: this. It's my understanding that you should have an onward journey out of Argentina before you're allowed to enter under a tourist visa. (Are you travelling on a US Passport? You'll need to pay about 160.00 bucks for a...