How to listTransaction Invoice customform?

@battk Thanks for answering but unfortunately it didn’t work what I want is

[baseRefList] => BaseRefList Object
                (
                    [baseRef] => Array
                        (
                            [0] => RecordRef Object
                                (
                                    [internalId] => 99
                                    [externalId] => 
                                    [type] => platformCore:RecordRef
                                    [name] => Standard Finance Charge
                                )

                            [1] => RecordRef Object
                                (
                                    [internalId] => 92
                                    [externalId] => 
                                    [type] => platformCore:RecordRef
                                    [name] => Standard Product Invoice
                                )

                            [2] => RecordRef Object
                                (
                                    [internalId] => 93
                                    [externalId] => 
                                    [type] => platformCore:RecordRef
                                    [name] => Standard Professional Invoice
                                )

                            [3] => RecordRef Object
                                (
                                    [internalId] => 87
                                    [externalId] => 
                                    [type] => platformCore:RecordRef
                                    [name] => Standard Progress Invoice
                                )

                            [4] => RecordRef Object
                                (
                                    [internalId] => 91
                                    [externalId] => 
                                    [type] => platformCore:RecordRef
                                    [name] => Standard Service Invoice
                                )

                        )

                )

and PHPToolkit provide the code for getting the custom form and I want same with query or API.The code are given below

$svr = new getSelectValueRequest();

$svr->fieldDescription = new GetSelectValueFieldDescription();

$svr->pageIndex = 1;
$priceFields = array(

'recordType' => RecordType::invoice,

'field' => 'customForm'

);
setFields($svr->fieldDescription, $priceFields);
$getResponse = $service->getSelectValue($svr);
echo "<pre>"; print_r($getResponse); echo "</pre>";

There is no REST webservices equivalent. Closest is found in the metadata, which was linked above. The metadata is unlikely to be usable for your purposes, though its likely to be place to find it when the invoice record is out of beta.