I recently received a new cover from Venezuela and, as for the first one, I got some difficulties to find information about the stamps. Anyway here is what I could gather. But first let me show you the cover.
The three stamps on the cover are part of a set of ten stamps issued on the 3rd of November 2006 to celebrate the Engineering faculty (Facultad de Ingeniería) that is a part of the Central University of Venezuela (Universidad Central de Venezuela, or UCV in short). The campus of this university located in Caracas is full of architectural and artistic works that are shown on the set.
The stamp on the left bottom corner pictures the school of Metallurgical Engineering and of Science of Materials. In front of the building there is a sculpture from Harry Abend (born 1937), a Polish born sculptor who lives in Venezuela.
The stamp on the right top corner pictures the school of Geophysics and the last one pictures a part of the library of the faculty. In fact the stamp pictures a stained glass from Alejandro Otero (1921-1990) a Venezuelan artist who decorated this library.
I was able to find a (very) small picture of the full set, the sheet of ten stamps. Here it is.
As you can see, the small label that is put in the top left corner of the cover is coming from the right corner of the sheet. Ipostel is the name of the Venezuelan postal administration.
The stamps are rather dark and the design is quite hard to read because, as you can guess on the picture, they have in the background a grey design that represents the logo of the university.
The postmark on the cover is rather traditional for a cover coming from South America: a blue rectangular cancel.