there is so many books and works on mahayana. do you specifically want to study madhyamaka since that is basically the best shastras available on the meaning of the prajnaparamita sutras i think. Then there is Mahayana mind training ( lojong ) texts which are quite a big bite to chew on, lots of work. then there is that which focuses on bodhicitta. hmmm, the emptiness doctrine has many different schools but certain works are recommended, classics by Nagarjuna, Chandrakirti, Aryadeva etc. and of course the paramitas.
you might be interested in this.http://www.amazon.com/The-Bodhisattva-P ... gy_b_img_y
i think this might be a good work to start to take the whole mahayana path as one book and then when you know a little bit about the different and concepts and methods, the different facets of mahayana, you could widen your study in more specific area of mahayana.
of course if you haven't heard of Amitabha Buddha i definitely recommend the Three Pure Land Sutras by BDK translation committee.
never forget amitabha
If the thought of demons
Never rises in your mind,
You need not fear the demon hosts around you.
It is most important to tame your mind within....
In so far as the Ultimate, or the true nature of being is concerned,
there are neither buddhas or demons.
He who frees himself from fear and hope, evil and virtue,
will realize the insubstantial and groundless nature of confusion.
Samsara will then appear as the mahamudra itself….