How to retrieve matching text field in multi level nested document

Hi everybody,

I have some problem with retrieving data with multi level nested document :

{
    "myindex": {
        "mappings": {
            "properties": {
                "analyzed": {
                    "properties": {
                        "details": {
                            "properties": {
                                "results": {
                                    "properties": {
                                        "body": {
                                            "properties": {
                                                "a": {
                                                    "properties": {
                                                        "externe": {
                                                            "type": "nested",
                                                            "properties": {
                                                                "href": {
                                                                    "type": "text"
                                                                },
                                                                "puissance": {
                                                                    "type": "integer"
                                                                }
                                                            }
                                                        },

How am I supposed to retrieve my href field for example ?