$re = '/((?<!t\. | § |tz |h. )\b[0-9][a-z]?\b(?!A))/m';
$str = 'Art. 19 Cst.
§ 39 VG
§ 39 Abs. 1 und 2 VG
Art. 19 BV
Art. 62 Abs. 1 BV
Art. 3 BV
Art. 62 Abs. 2 BV
Art. 19 und 62 BV
Art. 13 UNO-Pakt I
Art. 28 KRK
Art. 19 BV
Art. 62 BV
Art. 62 BV
Art. 62 BV
Art. 62 BV
Art. 27 BV
Art. 14 KV/ZH
Art. 19 BV
Art. 19 BV
Art. 116 KV/ZH
Art. 27 BV
Art. 62 BV
Art. 62 BV
Art. 62 BV
Art. 62 BV
Art. 19 BV
Art. 36 BV
§ 39 Abs. 1 VG
§ 39a Abs. 1 VG
§ 39 Abs. 1a VG
§ 39 Abs. 1 VG
§ 39 VG
§ 39 Abs. 2 VG
Art. 302 Abs. 1 ZGB
§ 39 Abs. 2 Satz 1 VG
Art. 19 BV
Art. 8 Abs. 1 und 2 BV
Art. 19 und Art. 62 Abs. 2 BV
§ 39 Abs. 1 und 2 VG
Art. 18 BV
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php