Lasagne with Bolognese sauce

It is necessary:

2 packages Bolognese sauce
15 fresh bark for lasagne,
100 g Parmesan cheese,
30 g butter,

For the bechamel sauce is needed:

1 l milk
100 g butter,
80 g flour
salt,
Pepper.

Preparation:
 
Prepare the Bolognese sauce as directed.
In a bowl, blend butter for cooking, add the flour and stir.
Cook for up to 3 minutes with constant stirring.
Add pre-warmed milk and let it boil with constant stirring 4 to 5 minutes.
Add salt and pepper.
Lasagne dough cut into strips about 10 cm wide and the length of what the frying pan.
In salt boiling water place three lasagne dough strips and cook for about half a minute and the same strip place in a bowl of cold water for about half a minute.
Arrange strips on a clean cloth to one another.
Butter grease baking pan.
Put row of Bolognese sauce.
Over it put row of the dough and turn row of Bolognese sauce and row of bechamel sauce, then grated Parmesan cheese. (This is repeated until it is consumed all the material).
The last row of the dough coat with butter and grated parmesan cheese.
Bake till golden brown.