Although very much a composer from the Romantic Period, the music of Brahms tended to be very strict in term of its observence of Classical form. The first movement of this Cello Sonata illustrates this with its beautifully constructed sonata form, yet the music is brim full of passion. In PDF format here is the Full Score of this work, plus the individual parts for Cello and Piano. You can also download this piece as a MIDI file or MP3 file. The video below illustrates shows a piano roll animation of the music, while below the video you can play the mp3 file and see the music before downloading.
Here is a video of Brahms' Cello Sonata in Em (1st movement):
The audio controls below allow you to play the mp3 version of Brahms' Cello Sonata in Em (1st movement) or you can download the MP3 file. You can also download the midi version of Brahms' Cello Sonata in Em (1st movement).
The image below is the first page of the sheet music, and here you can download the full sheet music for Brahms' Cello Sonata in Em (1st movement) in PDF format.