Reference of a Paper on Group Theory I was searching a paper of Tuan H. F. on "A Theorem about $p$-groups with abelian subgroup of index $p$". It is published in Acad. Sinica Science Record, 3(1950), 17-23.
I tried to get a copy of this paper, but I couldn't find through internet. Only one place, I found a link to this paper (see this). But again, there is a problem to access this paper. 
It will be great pleasure for me if one can show a link to the paper or at least the main theorem(s) in the paper proved by author.
 A: I transcribe here the results from the said paper in which main theorem states (with the proof omitted):

Theorem. If a nonabelian $p$-group $\mathfrak{G}$ of order $p^n$ contains an abelian
  subgroup $\mathfrak{A}$ of order $p^{n - 1}$ and if $\mathfrak{Z}$
  and $\mathfrak{K}$ denote respectively the centrum and the commutator subgroup
  of $\mathfrak{G}$, then
  $$\mathfrak{A}/\mathfrak{Z} \cong \mathfrak{K}$$
  and $\mathfrak{Z} \cap \mathfrak{K}$ is abelian of type $\left( p, p,
\cdots, p \right)$. Whence, denoting by $p^z$ and $p^k$ the orders
  of $\mathfrak{Z}$ and $\mathfrak{K}$ respectively, we have
  $$n = k + z + 1.$$

More generally:

Theorem'. If a $p$-group $\mathfrak{G}$ of order $p^n$ contains a maximal normal abelian subgroup $\mathfrak{A}$ with cyclic factor group $\mathfrak{G}/\mathfrak{A}$, and if  $\mathfrak{Z}$
  and $\mathfrak{K}$ denote respectively the centrum and the commutator subgroup
  of $\mathfrak{G}$, we have
  $$\mathfrak{A}/\mathfrak{Z}\cong\mathfrak{K}.$$
  Furthermore if $p^z$, $p^k$ and $p^d$ denote the orders of $\mathfrak{Z}$, $\mathfrak{K}$ and $\mathfrak{G}/\mathfrak{A}$ respectively, then all the elements of $\mathfrak{Z} \cap \mathfrak{K}$ have their orders not exceeding $p^d$, and
  $$n=k+z+d.$$

The extension:

Extension. Let $\mathfrak{G}$ be a $p$-group of order $p^n$. Let its class be $c$, its lower central series be
  $$\mathfrak{G}=\mathfrak{G}_1 \supset \mathfrak{K} = \mathfrak{G}_2 = (\mathfrak{G},\mathfrak{G})\supset \cdots \supset \mathfrak{G}_c \supset \mathfrak{G}_{c+1} =I.$$
  and its upper central series be
  $$\mathfrak{G}=\mathfrak{Z}_c\supset \mathfrak{Z}_{c-1} \supset \cdots \supset \mathfrak{Z}_1 = \mathfrak{Z} \supset \mathfrak{Z}_0=I.$$
  Let $\mathfrak{G}$ contain an abelian subgroup $\mathfrak{A}$ of order $p^{n-1}$, then we have
  $$\mathfrak{A}/\mathfrak{A}\cap\mathfrak{Z}_i\cong\mathfrak{G}_{i+1},\quad i=1,\cdots,c.$$
  In fact, for $i=1,\cdots,c-1$, $\mathfrak{A}$ must contain $\mathfrak{Z}_i$, and hence
  $$\mathfrak{A}/\mathfrak{Z}_i\cong\mathfrak{G}_{i+1},\quad i=1,\cdots,c-1.$$
  If we denote by $p^{z_i}$ and $p^{k_{i+1}}$ the orders of $\mathfrak{Z}_i$ and $\mathfrak{G}_{i+1}$, we have
  $$n=z_i+k_{i+1}+1,\quad i=1,\cdots,c-1.$$

A: The only reference I have indeed is only via Berkovich's book "Groups of Prime Power Order, Vol 1". I have to write out it as on my bookshelf and not pdf. There we have:
According to Tuan if a $p$ group $G$ has a normal abelian subgroup $A$ with cyclic quotient group $G/A$, then $A/(A\cap Z(G))\cong G'$ (see also I.M.Isaacs "Character Theory of finite groups, Acad. Press, N.Y. 1976" Lemma 12.12).
A group $G$ is said minimal nonabelian if it is non-abelian but all its proper subgroups are abelian.

