Трудности с многомерными массивами

$authors = [
 
1 => [
 
'name' => 'Александр Сергеевич',
 
'born' => '1799',
 
'email' => 'arap@pushkin.ru',
 
'books' => [
[
'title' => 'Лукоморье',
'creat' => '1829'
],
[
'title' => 'Царь Салтан',
'creat' => '1832'
]
]
],
 
2 => [
'name' => 'Лев Николаевич',
'born' => '1828',
'email' => 'lev@tolstoi.ru',
'books' => [
[
'title' => 'Детство',
'creat' => '1852'
],
[
'title' => 'Война и мир',
 
'creat' => '1863'
 
]
 
]
 
],
 
3 => [
 
'name' => 'Николай Васильевич',
 
'born' => '1809',
 
'email' => 'gogol@mogol.ru',
 
'books' => [
 
[
 
'title' => 'Вий',
 
'creat' => '1835'
 
]
 
]
 
]
 
];
 
foreach ($authors as $author) {
 
echo $author['name'] . " - " . $author['email'] . " - " . $author['born'] . "<br />";
 
}
 
echo "<br /><hr /><br />";
 
foreach ($authors as $author) {
 
foreach ($author['books'] as $book) {
 
echo $book['title'] . " - " . $author['name'] . " - " . $book['creat'] . "<br />";
 
}
 
}

$avtors = [
    ["Тургенев", "turgenev@knigi.ru","1818"],
    ["Толстой", "tolstoy@moscow.ru","1828"],
    ["Гайдар", "gaidar@moscow.ru","1904"]
];
 
//----------------------------
 
$knigi = [
    ["Отцы и дети", $avtors[0][0],"1862"],
    ["Война и мир", $avtors[1][0],"1869"],
    ["Тимур и его команда", $avtors[2][0],"1940"],
    ["Чук и Гек", $avtors[2][0],"1939"],
    ["Голубая чашка", $avtors[2][0],"1936"]
 
];
$result=array_merge($avtors, $knigi);
foreach ($result as $rest=>$rst){
    echo implode("-",$rst)."<br>";
}